Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Caramelized Onion and Tomato Tart Au Gratin

September 26, 2013Teresa

Caramelized Onion and Tomato Tart Au Gratin is absolutely A-M-A-Z-I-N-G!!! This delicious side dish includes lots of caramelized onions in a homemade pie crust. It’s topped with four cheeses! It’s layered with sliced tomatoes, several delicious herbs and has more cheese on top. Spectacular is about the only word worthy of this fabulous tomato tart recipe. My mouth is watering just thinking about the awesome texture and flavors of this tomato and onion pie.

Some of you follow me on Pinterest. Last week I pinned 20 or 30 different tomato tart recipes. I was trying to find one that I really wanted to try. I began seeing all these wonderful looking pictures of tomato tarts online. Finally I landed at this recipe, based on Ina Garten’s Tomato and Goat Cheese Tart. I liked several things from this recipe. Even though I had goat cheese on hand, I chose not to use it. Neither did I want to use the mayonnaise-dijon mustard combo I had seen in other recipes.

I took the idea for the caramelized onions from these two recipes. The idea of setting the tomatoes out on the counter to dehydrate for an hour came from Milk Glass Kitchen’s rendition. I used some of their seasonings, but departed completely from some of their other ingredients. Instead I used Asiago, Parmesan, and Fontina cheeses on the tart underneath the tomatoes. I used Pecorino Romano cheese on the top after I’d seasoned the tarts. All I can say about this tart is that the taste was fantastic.

It does take a few minutes to whip up a homemade pie crust. (For me, it takes about 5 to 10 minutes depending on how many crusts I’m making at one time). But you can substitute store bought pie crust if you don’t have time. The tomatoes need to be sliced, salted and set out on paper towels for at least an hour to drain. This helped the pie not become soupy.

The longest thing for me to do was caramelizing the onions. It seemed to take FOREVER! To my chagrin I’ve never caramelized onions before. I was afraid to have my heat too high and scorch them. As a result they probably took about one and a half hours before it was all said and done! Perhaps because I was doing two batches. Everyone else says you can do it in about 45 minutes. Be prepared for them to take a while to cook. This site was the most helpful in learning how to caramelize onions for the first time.

Here are a few of my recommendations: First, after you make the pie crust, set it aside and don’t put ANYTHING into the pie shell until you have all the components ready. If you allow the onions, cheeses, or tomatoes to sit in the pie for any length of time before baking, you will end up with a soggy crust.

This is the same for making fruit pies. Don’t allow the fruit mixture to sit in an unbaked pie shell for more than a minute or two before tossing the pie into the oven if you don’t want a soggy crust. Truthfully, you are better off getting everything else ready first, THEN make your pie crust. That way your pie crust won’t dry out while you’re getting everything else ready.

Second, caramelize the onions when you have plenty of time. You can even do these the night before and stir occasionally while you’re watching TV. Then store them in a refrigerator until ready to use. At your earliest opportunity, on the day you want to make the tart, slice the tomatoes. Then set them out on paper towels to drain, being sure to salt them generously. It doesn’t matter if they set out a few hours before you have time to get around to them. Just get them draining on the counter until you’re really ready to make the recipe.

You will be amazed at how much liquid will drain from the tomatoes. I made three different types of tarts at the same time. So I had tomatoes, heirloom tomatoes, grape tomatoes and zucchini all sitting out at the same time. There was probably a cup of liquid run-off from all of the stuff I did!

When you’re ready to assemble the tart, do this. Lay the caramelized onions in the bottom of the uncooked pie crust. Sprinkle three of the four cheeses over top of the onions. Place tomatoes over top of the cheeses in overlapping fashion. Sprinkle the tomatoes with all the seasonings. Then top everything with the pecorino romano cheese. As soon as you finish assembling all the ingredients, the tart/pie should go into the oven. It goes without saying that you need to have a preheated oven!

If you’re looking for a great new way to use up garden tomatoes or onions, then by all means consider this recipe. Just be prepared for the fact that it may take a few hours to get it all done from start to finish. Even still, you will sink your teeth into one of the most delicious, tantalizing tomato tarts you have EVER tasted. Caramelized Onion and Tomato Tart Au Gratin is the real deal! Oh, my, it’s one of those recipes I think I could eat almost every day! This healthy, low calorie, and tasty tart is excellent served as a side dish, but I also ate it as a main dish. Add a salad or bread, and it is yum, yum delicious. It’s also wonderful for breakfast. On top of that it reheats well to serve for leftovers.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Caramelized Onion and Tomato Tart Au Gratin is one of the BEST tasting tarts you will ever eat.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

This scrumptious tart recipe is sweetened a little by the caramelized onions.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

The savory blend of cheeses adds depth to a very rich tasting tomato tart. Caramelized Onion and Tomato Tart Au Gratin is a bit of work, but it’s SO worth it in the end! I served this first-try recipe to company and everyone loved it.

Here’s what I did.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Start with a batch of my Homemade Pie Crust recipe. I started out with 3 cups of flour (honestly, I don’t measure much, I go by texture, look, and feel), and that was enough crust to make 2 large torte pans like this, plus about 15-18 small miniature tart dishes.

Cut off the edge (and used all the leftover pieces for the small miniature tart dishes).

This is what the tart dish looks like after fitting it with crust. This tart dish is not as deep as a normal pie plate. Honestly, it is better for you to make up all the other ingredients and have them ready before making your pie crust. You don’t want your pie crust sitting out too long and getting dried out.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Slice onions and separate into rings. Place some olive oil in a skillet over medium heat and begin sauteing onions. Continue sauteing onions.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

After about a half hour, add salt, pepper, thyme, and white wine vinegar or white wine. It took forever for my onions to caramelize.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

I’m not sure if my heat was too low or I was stirring them too frequently. After cooking them an hour and a half I had to get going with the rest of the recipe so it would be ready on time for dinner.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Slice down tomatoes and set on paper towels. Generously sprinkle with salt. Allow the tomatoes to drain (dehydrate) at least one hour. Mine were laying out about three hours before I got around to them.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Once all your ingredients are ready start piling them into the pie shell. Spread caramelized onions over the bottom of your pastry shell.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

I used these cheeses.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Sprinkle parmesan cheese over top of the onions. 

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Now sprinkle with Asiago cheese.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Sprinkle with Fontina cheese.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Layer tomatoes in an overlapping fashion to completely cover the tart dish. 

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

I used these seasonings to spice the dish.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Sprinkle tomatoes with rubbed (not ground) sage, rosemary, oregano and basil. I grabbed two or three pinches and crushed the leaves in between my thumb and fingers a little bit before adding on top. It was probably at least 1/2 tsp. of each seasoning. Use more if you like a lot of seasoning on your tomatoes! 

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Sprinkle with finely grated pecorino romano cheese. 

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Bake at 350 about 20-30 minutes until tomatoes are tender and crust is lightly browned. Here’s what my tart looked like just out of the oven.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Caramelized onions and tomatoes are a wonderful combination. Then when you add all the cheese and seasonings – WOW! This recipe just pops with flavor. Even the kids enjoyed this tasty tomato tart recipe. 

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

This spectacular Caramelized Onion and Tomato Tart Au Gratin is a great pie to use up garden veggies like tomatoes or onions.

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

You can also refrigerate or freeze the tart and reheat it for later. (I froze some of them and reheated the tarts the following week for additional company).

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

This is a terrific side dish for dinner or as a breakfast entree. It’s especially nice for holiday meals.

Here’s the recipe.

CARMELIZED ONION AND TOMATO TART AU GRATIN

(Recipe inspired from Milk Glass Kitchen which is no longer a viable blog, source: inspired from Ina Garten)

Print Recipe
Caramelized Onion and Tomato Tart Au Gratin BigOven - Save recipe or add to grocery list Yum
This amazing vegetable pie has spectacular flavors using four different cheeses, tomatoes and caramelized onions. A fabulous Meatless Mondays recipe. It's also terrific as a side dish or for breakfast. Uses Parmesan, Asiago, Fontina and Romano cheeses. Even kids enjoy this fantastic tomato pie recipe.
Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay
Prep Time 15 minutes
Cook Time 30 minutes
Servings
Ingredients
Prep Time 15 minutes
Cook Time 30 minutes
Servings
Ingredients
Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay
Instructions
  1. Slice tomatoes and lay out on paper towels.
  2. Sprinkle very generously with salt and allow to set out on counter and drain for at least one hour.
  3. Add olive oil to a large cast-iron skillet and heat over low to medium heat.
  4. Add onions and cook about 30 minutes turning occasionally so onions don’t burn.
  5. Add thyme, salt, pepper, and white wine vinegar.
  6. Continue cooking another 15-30 minutes or however long it takes to caramelize the onions.
  7. You may need to add a little water so the onions don’t stick too much.
  8. Use a heavy-duty metal spatula to scrape onions from pan if necessary.
  9. Prepare pie crust and fit into a large 10-inch tart pan.
  10. When all the other ingredients are ready, layer the caramelized onions on the bottom of the tart pan.
  11. Sprinkle Parmesan, Asiago and Fontina cheeses over top of the onions.
  12. Add tomato slices overlapping the edges.
  13. Sprinkle tomatoes with basil, oregano, rosemary, and rubbed sage leaves.
  14. Then sprinkle pecorino romano cheese over top of all.
  15. Bake at 350 for about 20-30 minutes until tomatoes are tender and crust is done.
Recipe Notes
NOTE: Preparation time does NOT include time required to caramelize onions. That may take an additional hour!
 
NOTE: Preparation time does NOT include time required to make pie crust.
 
NOTE: Do not start adding things to the pie shell until you have everything ready and it's ready to go into a preheated oven. Otherwise, you will end up with a soggy pie crust.
 
NOTE: You must lay out the tomatoes on the counter and salt them down so they drain, otherwise you will have a very mushy, juicy pie.
Recipe inspired from Ina Garten, the Barefoot Contessa via Food Network.
© Can’t Stay Out of the Kitchen

 

[b]Caramelized Onion and Tomato Tart Au Gratin[/b]
 
Recipe Type: Vegetable Pie
Cuisine: American
Author: Teresa Ambra inspired from Milk Glass Kitchen (which no longer operates their blog); source: inspired from [url href=”http://www.foodnetwork.com/recipes/ina-garten/tomato-and-goat-cheese-tarts-recipe.html” target=”_blank” title=”tomato and goat cheese tarts”]Ina Garten[/url], the Barefoot Contessa
Prep time:
Cook time:
Total time:
Serves: 8
This amazing vegetable pie has spectacular flavors using four different cheeses, tomatoes and caramelized onions. A fabulous Meatless Mondays recipe.
Ingredients
  • 1 whopper-sized onion, sliced and separated into rings (about 1-lb. or two large onions)
  • 2 tbsp. olive oil
  • 3 tbsp. white wine vinegar
  • ½ tsp. thyme
  • ½ tsp. kosher salt
  • ¼ tsp. pepper
  • 3 large tomatoes, sliced
  • ½ cup shredded parmesan cheese
  • ½ cup shredded Asiago cheese
  • ½ cup shredded fontina cheese
  • ¼ to ½ cup finely grated pecorino romano cheese
  • ½ tsp. basil
  • ½ tsp. oregano
  • ½ tsp. rosemary, crushed
  • ½ tsp. rubbed sage leaves
  • recipe for [url href=”http://cantstayoutofthekitchen.com/2012/12/05/homemade-pie-crust/” target=”_blank” title=”homemade pie crust”]single crust plain pastry[/url]
Instructions
  1. Slice tomatoes and lay out on paper towels.
  2. Sprinkle very generously with salt and allow to set out on counter and drain for at least one hour.
  3. Add olive oil to a large cast-iron skillet and heat over low to medium heat.
  4. Add onions and cook about 30 minutes turning occasionally so onions don’t burn.
  5. Add thyme, salt, pepper, and white wine vinegar.
  6. Continue cooking another 15-30 minutes or however long it takes to caramelize the onions.
  7. You may need to add a little water so the onions don’t stick too much.
  8. Use a heavy-duty metal spatula to scrape onions from pan if necessary.
  9. Prepare pie crust and fit into a large 10-inch tart pan.
  10. When all the other ingredients are ready, layer the caramelized onions on the bottom of the tart pan.
  11. Sprinkle Parmesan, Asiago and Fontina cheeses over top of the onions.
  12. Add tomato slices overlapping the edges.
  13. Sprinkle tomatoes with basil, oregano, rosemary, and rubbed sage leaves.
  14. Then sprinkle pecorino romano cheese over top of all.
  15. Bake at 350 for about 20-30 minutes until tomatoes are tender and crust is done.
 
Notes
Preparation time does NOT include time required to caramelize onions. That may take an additional hour![br][br]Preparation time does NOT include time required to make [url href=”http://cantstayoutofthekitchen.com/2012/12/05/homemade-pie-crust/” target=”_blank” title=”homemade pie crust”]pie crust[/url].[br][br]Do not start adding things to the pie shell until you have everything ready and it’s ready to go into a preheated oven. Otherwise, you will end up with a soggy pie crust.[br][br]You must lay out the tomatoes on the counter and salt them down so they drain, otherwise you will have a very mushy, juicy pie.
Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Doesn’t Caramelized Onion and Tomato Tart Au Gratin look delicious? This fantastic tart is sure to tantalize your taste buds! You know a recipe’s a hit when little children love it!

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

I’m starting to drool over those caramelized onions. They added so much flavor to the recipe. 

Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay

Our family and company really enjoyed this version of Caramelized Onion and Tomato Tart Au Gratin. Because I didn’t add the ingredients to the pie crust until right before baking, the crust came out wonderfully. No soggy crust! Inhale, exhale, now drool!

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Creamy Avocado and Tomato Pasta | Can't Stay Out of the Kitchen | this easy and delightful #pasta #recipe is utterly amazing. The #Basil & #avocado sauce makes this dish fantastic. It also includes #tomatoes, #PineNuts & #ParmesanCheese. This is totally awesome for #MeatlessMondays or on days when you're short on time. I used #GlutenFree #noodles but you can use any kind. #cheese #GlutenFreeMainDish #CreamyAvocadoAndTomatopasta

Skinny Roasted Vine-Ripe Tomatoes

Skinny Roasted Vine-Ripe Tomatoes | Can't Stay Out of the Kitchen | fantastic #sidedish that's wonderful for any occasion including company. Uses #tomatoes & fresh herbs. Tomatoes made this way are so, so mouthwatering. #vegan #glutenfree #healthy #lowcalorie
Print Recipe
Caramelized Onion and Tomato Tart Au Gratin BigOven - Save recipe or add to grocery list Yum
This amazing vegetable pie has spectacular flavors using four different cheeses, tomatoes and caramelized onions. A fabulous Meatless Mondays recipe. It's also terrific as a side dish or for breakfast. Uses Parmesan, Asiago, Fontina and Romano cheeses. Even kids enjoy this fantastic tomato pie recipe.
Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay
Prep Time 15 minutes
Cook Time 30 minutes
Servings
Ingredients
Prep Time 15 minutes
Cook Time 30 minutes
Servings
Ingredients
Caramelized Onion and Tomato Tart Au Gratin | Can't Stay Out of the Kitchen | this delectable tart is filled with #tomatoes, 4 cheeses & #CaramelizedOnions. It is so mouthwatering. Good as a #SideDish or for #Breakfast. #TomatoTart #TomatoPie #RomanoCheese #ParmesanCheese #AsiagoCheese #FontinaCheese #Holiday #HolidaySideDish #HolidayBreakfast #Easter #MothersDay
Instructions
  1. Slice tomatoes and lay out on paper towels.
  2. Sprinkle very generously with salt and allow to set out on counter and drain for at least one hour.
  3. Add olive oil to a large cast-iron skillet and heat over low to medium heat.
  4. Add onions and cook about 30 minutes turning occasionally so onions don’t burn.
  5. Add thyme, salt, pepper, and white wine vinegar.
  6. Continue cooking another 15-30 minutes or however long it takes to caramelize the onions.
  7. You may need to add a little water so the onions don’t stick too much.
  8. Use a heavy-duty metal spatula to scrape onions from pan if necessary.
  9. Prepare pie crust and fit into a large 10-inch tart pan.
  10. When all the other ingredients are ready, layer the caramelized onions on the bottom of the tart pan.
  11. Sprinkle Parmesan, Asiago and Fontina cheeses over top of the onions.
  12. Add tomato slices overlapping the edges.
  13. Sprinkle tomatoes with basil, oregano, rosemary, and rubbed sage leaves.
  14. Then sprinkle pecorino romano cheese over top of all.
  15. Bake at 350 for about 20-30 minutes until tomatoes are tender and crust is done.
Recipe Notes
NOTE: Preparation time does NOT include time required to caramelize onions. That may take an additional hour!
 
NOTE: Preparation time does NOT include time required to make pie crust.
 
NOTE: Do not start adding things to the pie shell until you have everything ready and it's ready to go into a preheated oven. Otherwise, you will end up with a soggy pie crust.
 
NOTE: You must lay out the tomatoes on the counter and salt them down so they drain, otherwise you will have a very mushy, juicy pie.
Recipe inspired from Ina Garten, the Barefoot Contessa via Food Network.
© Can’t Stay Out of the Kitchen

21 Comments

  • Brian

    September 23, 2017 at 11:49 pm

    I’ve never heard of pie parties, but tonight we went to our first one. Such a great idea… each guest is asked to bring their choice of a savory, fruit, custard or vegan pie. I’m happy to say that I made this tomato pie and from at least 10 other options in the savory category I walked away with first prize. It really is that good. Thanks for the share.

    1. Teresa

      September 24, 2017 at 5:21 pm

      Oh, Brian, I am so glad!!! I know this pie/tart is a good bit of work (especially if you make your own pie crust), but we thought this savory pie was amazing. So glad you won first prize and everyone enjoyed it. Thanks for stopping by to let me know.

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  • Tamara Leigh: The Kitchen Novelist

    September 27, 2013 at 7:14 pm

    I think “DELISH” Teresa!

    1. Teresa

      September 27, 2013 at 8:32 pm

      You gotta try it and let me know what everyone thought! I served a different variation tonight and everyone loved them. I had baked them, froze them, and then reheated them and they were still wonderful!

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  • Shari Kelley

    September 26, 2013 at 5:32 pm

    I absolutely love caramelized onions! The combination of cheeses sounds so good, too. Thanks for sharing!

    1. Teresa

      September 27, 2013 at 9:11 am

      These turned out so, so well. We loved them!

  • Tamara Leigh: The Kitchen Novelist

    September 26, 2013 at 5:24 pm

    Yum, Teresa! And so gorgeous! One of the dinners on my new menu is a tomato and onion tart and I’m trying to decide how to add more protein so I can pass it off as an entree for my meat-lovin’ guys. So either quite a bit more cheese or, perhaps, chicken. Oh, how I wish I had garden tomatoes–may have to visit the farmer’s market inconveniently located though it is. But I’m inspired 🙂

  • Kerry

    September 26, 2013 at 5:10 pm

    So glad you loved this recipe! Ina is one of my favorites and this is a great example of her simple and delicious style. Your addition of the harder cheeses looks yummy!

    1. Teresa

      September 26, 2013 at 5:13 pm

      You know, it was SO wonderful. I will probably try it with the goat cheese sometime but really wanted to try out this with the fontina and other cheeses and see what it turned out like. Thanks for all the tips about laying the tomatoes out on the counter. I would never have thought to do that, but it really made all the difference in the world!

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