Caramelized Onion, Zucchini, Tomato and Mushroom Tart is awesome! This is another of those “to-die-for” tarts I made a couple of weeks ago. Caramelized Onions, slices of zucchini, tomatoes and mushrooms filled my Homemade Pie Crust-lined tart pan. The veggies were seasoned with lots of delicious Italian seasonings, and smothered in four different hard cheeses: Asiago, Parmesan, Fontina, and Pecorino Romano.

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Yum, yum, good was the reaction from our guests when I served this wonderful tart. This scrumptious tart cannot be classified with a “quick and easy ” description since it is a lot more involved and time-consuming. But it can certainly be classified as one of the BEST veggie tarts you’ll ever eat! Those of you still reaping veggies like tomatoes, onions, or zucchini from your garden will love being able to use them in this tasty recipe.

This lovely tart can be made as a side dish or as a main dish–particularly on Meatless Mondays. It’s very hearty, filling and satisfying, plus it just pops with flavor on those taste buds. It’s also a great breakfast entree.

It’s not excessively high in calories and is certainly a lot healthier than tarts or pies made with canned soups, gravy mix, ranch dressing mix and other ingredients with a lot of MSG, preservatives, and fillers. I know those foods have their place in cooking but I try to limit my use of them as much as possible. When I do, I find I don’t crave food all the time or have such an enormous appetite as when I eat something with MSG, sugar, or high fructose corn syrup.

Making up a Caramelized Onion, Zucchini, Tomato and Mushroom Tart is a great way to use up garden produce. If you don’t have time to make your own Homemade Pie Crust, than simply use a store bought crust.

Here are a few recommendations when making this tart: First, plan plenty of time because it will take about an hour to caramelize the onions fully and you need to lay the tomatoes and zucchini out on the counter to drain for at least an hour as well. This will help prevent too much liquid in the pie which causes a soggy crust.

Second, don’t place any of the filling in the pie crust until it is all ready to go (including having the oven at the preheated temperature). Leaving any kind of filling ingredients in a tart or pie shell and not baking immediately will cause a soggy crust.

Third, while I provide some detail for caramelizing the onions, if you need more explicit directions on how to do this than check out this post. Fourth, don’t make the pie crust for the tart until after the onions are caramelized and the tomatoes and zucchini have drained. Otherwise, the pie crust will dry out and get brittle.

If you’re looking for a marvelous tart recipe with radically amazing taste than please consider making up a Caramelized Onion, Zucchini, Tomato and Mushroom Tart sometime soon. Neither you, nor your family (or guests) will be disappointed with this sensational tart. The flavors are delectable and you will berate yourself for making ONLY one! 🙂

Usually I send a lot of leftovers home with our guests, but I was rather selfish with this tart and kept all the leftovers for my lunch the next day! This tasty tart even reheats well. You can also freeze the tart before or after baking and bake again (which is what I did for the third kind of tarts I made–which will be posted at a later time)!

Caramelized Onion, Zucchini, Tomato and Mushroom Tart is a sumptuous main dish recipe for Meatless Mondays.

Here’s a serving of this delicious tart.

This special tart is filled with four different cheeses: Romano, Asiago, Fontina and Parmesan.

Here’s what I did.

Fit Homemade Pie Crust or store bought pie crust in tart dish. Trim off edges. I highly recommend you don’t make the crust until the onions are caramelized and the tomatoes and zucchini have drained so the crust doesn’t dry out.

Slice tomatoes and set out on paper towels to drain. Sprinkle very generously with salt. The tomatoes need to drain at least an hour. Mine were actually on the counter about three hours before I used them.

Slice zucchini and lay out on paper towels to drain. Sprinkle the zucchini also very generously with salt.  The zucchini needs to drain at least an hour. Mine was actually on the counter about three hours before I used it.

Add a little olive oil to a large skillet and begin sauteing the onions over a medium heat.

Continue cooking and turning occasionally for about a half hour. Be careful that the heat is not so hot that the onions scorch, or that you turn the onions so frequently that they don’t brown and caramelize.

Season onions with salt, pepper, thyme and white wine vinegar.

Keep sauteing the onions until they caramelize.

You may have to add a little water to keep them from sticking too much to the pan.

Mine took about an hour and a half to get to this point. They should cook down in 45 minutes. I probably had my heat too low and turned the onions too frequently because I was afraid they’d scorch. 

Once the onions are caramelized and the tomatoes and zucchini have drained it’s time to layer your tart. Don’t begin until everything is in place otherwise your crust will become soggy. Place the caramelized onions in the tart dish.

Sprinkle parmesan cheese over top of the onions.

Add asiago cheese. 

Add fontina cheese.

Add a layer of zucchini.

Add a layer of tomatoes overlapping each other and then add a small layer of zucchini slices in the middle of the tart in a ring shape. Add sliced mushrooms around the edge.

Sprinkle with seasonings and pecorino romano cheese. Bake at 350 about 20-25 minutes or until done.

Here the tart is just out of the oven. Serve immediately. To serve the tart: slice in eighths.

Caramelized Onion, Zucchini, Tomato and Mushroom Tart is wonderful comfort food.

This is also delightful as a side dish for fish or chicken.

The savory flavors of the cheese and herbs with the added sweetness of caramelized onions are amazing. Using four different cheeses adds depth of flavor.

This is a fantastic breakfast entree for a company or holiday breakfast.

Here’s the recipe.

CARAMELIZED ONION, ZUCCHINI, TOMATO AND MUSHROOM TART

(My own concoction)

Caramelized Onion, Zucchini, Tomato and Mushroom Tart

Teresa Ambra

This luscious tart is filled with caramelized onions, zucchini, tomatoes and mushrooms. It also includes fontina, asiago, parmesan and romano cheese for additional full-bodied flavor. This tart is terrific for Meatless Mondays or as an entree for company or holiday breakfasts. If you enjoy Vegetarian meals, this one will knock your socks off!

No ratings yet

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Prep Time 2 hours hrs

Cook Time 25 minutes mins

Total Time 3 hours hrs 25 minutes mins

Course Breakfast, Veggie/Casserole/Pie

Cuisine American

Servings 8

Calories 233 kcal

Equipment

• 1 10-inch pie plate or torte pan
• 1 sharp knife to cut vegetables
• 1 large skillet
• 1 spatula
• measuring cups
• measuring spoons

Ingredients

  

1x2x3x

• 1 extra large onion 1-lb. onion or two large onions
• 1/2 tsp. sea salt or kosher salt
• 1/4 tsp. pepper
• 1/2 tsp. dried thyme
• 3 tbsp. white wine vinegar
• 1 medium zucchini sliced
• 3 large tomatoes sliced
• 4 oz. fresh mushroom halves sliced
• 1/2 tsp. dried basil
• 1/2 tsp. dried oregano
• 1/2 tsp. rubbed sage leaves
• 1/2 tsp. dried crushed rosemary
• 1/2 cup pecorino romano cheese finely grated
• 1/2 cup parmesan cheese shredded
• 1/2 cup fontina cheese shredded
• 1/2 cup asiago cheese shredded
• 1 Homemade Pie Crust or plain pastry

Instructions

 

• Slice tomatoes and zucchini and lay on paper towels on countertop.
• Sprinkle very generously with salt and allow to drain a minimum of one hour.
• Meanwhile, heat olive oil in a large cast-iron skillet or other skillet to low to medium heat.
• Slice onions and add to skillet.
• Sauté about 30 minutes turning occasionally so onions don’t burn.
• Add salt, pepper, thyme and white wine vinegar.
• Continue cooking and turning another 15-30 minutes until onions turn a dark amber color.
• You may have to add a little water so the onions don’t stick.
• Use a heavy metal spatula to remove any onions stuck on the bottom of the pan. Set aside.
• Prepare your pastry and gently fit it into a 10-inch torte pan.
• Once onions, tomatoes and everything else is ready place caramelized onions in bottom of torte pan.
• Then sprinkle with Parmesan, Fontina and Asiago cheeses.
• Layer zucchini in torte pan but do not overlap edges.
• Add tomatoes but overlap them using all.
• Place the remaining zucchini slices in the center of the torte pan overlapping in a circle.
• Place mushroom halves around the outside border of the torte pan.
• Sprinkle with basil, oregano, rubbed sage leaves, and rosemary.
• Then sprinkle the finely grated pecorino romano cheese over top.
• Bake at 350° for about 20-25 minutes until crust is done and veggies are cooked fork-tender.

Notes

^© Can’t Stay Out of the Kitchen

Nutrition

Calories: 233kcalCarbohydrates: 18gProtein: 11gFat: 14gSaturated Fat: 6gPolyunsaturated Fat: 1gMonounsaturated Fat: 5gCholesterol: 26mgSodium: 649mgPotassium: 318mgFiber: 2gSugar: 3gVitamin A: 373IUVitamin C: 12mgCalcium: 299mgIron: 2mg

Keyword breakfast, brunch, cheese, mushrooms, onions, pie, side dish, tomatoes, zucchini

Tried this recipe?Let us know how it was!

You can always add more layers or more mushrooms if you desire. I’m ready for a bite of this veggie pie right now!

Doesn’t Caramelized Onion, Zucchini, Tomato and Mushroom Tart look spectacular?  We loved the sensational taste of this tart recipe. You may want to make two of these tarts. Everyone will be wanting seconds!

You may also enjoy these delicious recipes!

Cherry Tomato Cobbler

Zucchini and Tomato Parmesan Casserole

Escalloped Tomatoes

Caramelized Onion, Zucchini, Tomato and Mushroom Tart

Teresa Ambra

This luscious tart is filled with caramelized onions, zucchini, tomatoes and mushrooms. It also includes fontina, asiago, parmesan and romano cheese for additional full-bodied flavor. This tart is terrific for Meatless Mondays or as an entree for company or holiday breakfasts. If you enjoy Vegetarian meals, this one will knock your socks off!

No ratings yet

Print Recipe Pin Recipe

Prep Time 2 hours hrs

Cook Time 25 minutes mins

Total Time 3 hours hrs 25 minutes mins

Course Breakfast, Veggie/Casserole/Pie

Cuisine American

Servings 8

Calories 233 kcal

Equipment

• 1 10-inch pie plate or torte pan
• 1 sharp knife to cut vegetables
• 1 large skillet
• 1 spatula
• measuring cups
• measuring spoons

Ingredients

  

1x2x3x

• 1 extra large onion 1-lb. onion or two large onions
• 1/2 tsp. sea salt or kosher salt
• 1/4 tsp. pepper
• 1/2 tsp. dried thyme
• 3 tbsp. white wine vinegar
• 1 medium zucchini sliced
• 3 large tomatoes sliced
• 4 oz. fresh mushroom halves sliced
• 1/2 tsp. dried basil
• 1/2 tsp. dried oregano
• 1/2 tsp. rubbed sage leaves
• 1/2 tsp. dried crushed rosemary
• 1/2 cup pecorino romano cheese finely grated
• 1/2 cup parmesan cheese shredded
• 1/2 cup fontina cheese shredded
• 1/2 cup asiago cheese shredded
• 1 Homemade Pie Crust or plain pastry

Instructions

 

• Slice tomatoes and zucchini and lay on paper towels on countertop.
• Sprinkle very generously with salt and allow to drain a minimum of one hour.
• Meanwhile, heat olive oil in a large cast-iron skillet or other skillet to low to medium heat.
• Slice onions and add to skillet.
• Sauté about 30 minutes turning occasionally so onions don’t burn.
• Add salt, pepper, thyme and white wine vinegar.
• Continue cooking and turning another 15-30 minutes until onions turn a dark amber color.
• You may have to add a little water so the onions don’t stick.
• Use a heavy metal spatula to remove any onions stuck on the bottom of the pan. Set aside.
• Prepare your pastry and gently fit it into a 10-inch torte pan.
• Once onions, tomatoes and everything else is ready place caramelized onions in bottom of torte pan.
• Then sprinkle with Parmesan, Fontina and Asiago cheeses.
• Layer zucchini in torte pan but do not overlap edges.
• Add tomatoes but overlap them using all.
• Place the remaining zucchini slices in the center of the torte pan overlapping in a circle.
• Place mushroom halves around the outside border of the torte pan.
• Sprinkle with basil, oregano, rubbed sage leaves, and rosemary.
• Then sprinkle the finely grated pecorino romano cheese over top.
• Bake at 350° for about 20-25 minutes until crust is done and veggies are cooked fork-tender.

Notes

^© Can’t Stay Out of the Kitchen

Nutrition

Calories: 233kcalCarbohydrates: 18gProtein: 11gFat: 14gSaturated Fat: 6gPolyunsaturated Fat: 1gMonounsaturated Fat: 5gCholesterol: 26mgSodium: 649mgPotassium: 318mgFiber: 2gSugar: 3gVitamin A: 373IUVitamin C: 12mgCalcium: 299mgIron: 2mg

Keyword breakfast, brunch, cheese, mushrooms, onions, pie, side dish, tomatoes, zucchini

Tried this recipe?Let us know how it was!