Tomato, Spinach, Onions Tart ~ veg



Because I’m still in heirloom tomato mood. I’m making tomato, spinach, and caramelized onion tart today!

This tart has a flaky crust and loaded with yummy vegetables in it. I purposedly put just enough liquid to cover the vegetables because I want to taste the vegetables and not the custard. Rolling the tart dough is also an important step, so you’ll get thin, crispy, and crunchy tart crust. Therefore, make sure the dough is rolled out thin. You can easily make the dough ahead of time and freeze them for future use.

My key to save my preparation time in cooking is to prepare my component ahead of time, which means that I make (almost) anything in a bigger batch. For instance, I made a big batch of tart dough way earlier in a month and froze them. By doing that, I skip the step of making my tart dough. You can easily do the same thing with pizza dough, bone broth, sauces, or even cookie dough. This process alone will save you about 30 minutes in preparation!

This tart is so adaptable, you can almost add any favorite vegetables in it. So the next time you are getting tired of making pizza, try this tart recipe and have your lunch ready in less than 30 minutes!

Tomato, Spinach, Caramelized Onion Tart

Delicious vegetable tart with a thin and flaky crust
Course dinner, lunch, snacks
Cuisine American, French, Italian
Keyword easy, onion, spinach, tart, tomatoes, vegetarian
Prep Time 20 minutes
Cook Time 25 minutes
Servings 9 inches round tart ring
Author mixingbowlnyc
Cost 6


Tart Crust

  • 500 grams all-purpose flour
  • ½ teaspoon salt
  • 250 grams cold butter, cut into cubes
  • 1 egg yolk
  • 250 ml cold water

Tart Liquid Batter

  • 1/2 cup heavy cream or milk
  • 1 egg
  • salt and pepper

Vegetables for the tart

  • cup heirloom tomatoes, sliced
  • 1 cup cooked spinach. (you can boil, or sauteed)
  • ½ cup caramelized onions (sauteed in a low flame onion slices until they're caramelized)


  • To make tart dough
  • Using a pastry cutter or a food processor, cut the butter into the mixture until it resembles a coarse meal (pea-sized bits with a few larger bits)
  • Add ice-cold water (don't put ice cubes into the mixture) a little at a time and begin to pulse the food processor. If you are using hands, do the same method. Stop adding water when the dough begins to form large clumps and comes together when you form it into a ball.
  • Measure the dough about 5 ounces, and wrap them individually to put them in the fridge.
  • Let the dough rest for at least 30 minutes.
  • Pre-heat the oven for 375°F
  • In the meantime, start caramelize onions.
  • Prepare the vegetables by slicing tomatoes, and cook the spinach.
  • Mix all ingredients for the tart liquid batter in a separate bowl.
  • After 30 minutes, or when the dough is not too soft to roll. Take the tart dough out of the fridge, and begin to roll.
  • Cover the tart rings with the tart dough.
  • Let the dough covered tart ring in a fridge one more time to chill. (this process will allow the butter to hardened, creating a flaky and crust)
  • Cover the tart ring with a parchment paper and place dry beans or dry rice on top to pre-bake.
  • Pre-bake the tart dough, for 10-15 minutes.
  • After the first pre-baked, scattered all vegetables on the tart dough then pour over the liquid batter just enough to cover the vegetables. (it may look too little, but trust me it will taste great!)
  • Bake the tart in the oven for 20-30 minutes, or until the custard is set and the vegetables are roasted.


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