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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

Teresa Ambra
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.
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Prep Time 15 minutes
Cook Time 30 minutes
Total Time 45 minutes
Course Breakfast, Side Dish, Vegetable Pie
Cuisine American
Servings 8
Calories 243 kcal

Equipment

  • 1 10-inch tart dish or pie plate
  • 1 sharp knife to cut vegetables
  • 1 large skillet
  • 1 wooden spoon
  • 1 spatula
  • measuring cups
  • measuring spoons

Ingredients
  

  • 1 extra large onion sliced and separated into rings, about 1-lb. or two large onions
  • 2 tbsp. olive oil
  • 3 tbsp. white wine vinegar
  • 1/2 tsp. dried thyme
  • 1/2 tsp. sea salt or Kosher salt
  • 1/4 tsp. ground black pepper
  • 3 large tomatoes sliced
  • 1/2 cup parmesan cheese shredded
  • 1/2 cup asiago cheese shredded
  • 1/2 cup fontina cheese shredded
  • 1/4 to 1/2 cup pecorino romano cheese finely grated
  • 1/2 tsp. dried basil
  • 1/2 tsp. dried oregano
  • 1/2 tsp. dried rosemary crushed
  • 1/2 tsp. dried rubbed sage leaves
  • 1 recipe for single crust plain pastry

Instructions
 

  • Slice tomatoes and lay out on paper towels.
  • Sprinkle very generously with salt and allow to set out on counter and drain for at least one hour.
  • Add olive oil to a large cast-iron or other skillet and heat over low to medium heat.
  • Add onions and cook about 30 minutes turning occasionally so onions don’t burn.
  • Add thyme, salt, pepper, and white wine vinegar.
  • Continue cooking another 15-30 minutes or however long it takes to caramelize the onions.
  • You may need to add a little water so the onions don’t stick too much.
  • Use a heavy-duty metal spatula to scrape onions from pan if necessary.
  • Prepare pie crust and fit into a large 10-inch tart pan.
  • When all the other ingredients are ready, layer the caramelized onions on the bottom of the tart pan.
  • Sprinkle Parmesan, Asiago and Fontina cheeses over top of the onions.
  • Add tomato slices overlapping the edges.
  • Sprinkle tomatoes with basil, oregano, rosemary, and rubbed sage leaves.
  • Then sprinkle pecorino romano cheese over top of all.
  • Bake at 350 for about 20-30 minutes until tomatoes are tender and crust is done.

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

Nutrition

Calories: 243kcalCarbohydrates: 17gProtein: 9gFat: 15gSaturated Fat: 6gPolyunsaturated Fat: 1gMonounsaturated Fat: 7gCholesterol: 23mgSodium: 611mgPotassium: 206mgFiber: 2gSugar: 2gVitamin A: 312IUVitamin C: 7mgCalcium: 262mgIron: 2mg
Keyword breakfast, cheese, onions, side dish, tomatoes
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