Summer heirloom tomato tart from scratch with a savory whole wheat crust, vegan ricotta, sweet caramelized onions and thin slices of colorful heirloom tomatoes. A free-form tart recipe finished with a fresh basil chiffonade or crispy fried sage leaves, it can be an appetizer or an entree alongside a simple arugula or baby kale salad. Simply divine!

Heirloom Tomato Tart

The French version of pizza, an easy rustic tart made by hand and topped with the best of summer’s tomatoes or favorite veggies. Nothing fancy, you really don’t have to be a pâtissier to make it, the hardest thing is waiting for it to come out of the oven. Resist the temptation to take it out too soon, let it get golden brown, flaky and crispy.

The Tart Crust or Pâte Brisée

It’s simple, doesn’t require a tart pan, made with whole wheat pastry flour and vegan European style butter. A quick 10 minute freeze of the butter is recommend so it can be easily grated over the flour. Just like making biscuits or pie crust, you want to work fast with cold ingredients but don’t fuss too much over it. Take it to the next level by mixing in a tablespoon of caraway or fennel seeds. All things considered, if you want to use a store bought pie crust or some frozen puff pastry that’s fine too.

Tomato Tart Ingredients

caramelized onions – use your biggest skillet and double batch it. They are perfect on so many other things besides this tart.
heirloom tomatoes – the best tasting of all tomatoes, sweet not acidic, without a doubt the best tomatoes for tomato tart. Go for different sizes and a mix of colors layering the largest slices on the bottom and topping with smaller ones.
cashew ricotta cheese – this creamy fromage frais is totally optional but recommended, makes a great canvas for the caramelized onions to sink into and results in a more filling tart. A layer of chive pesto makes for a lovely alternative.

How to Make Heirloom Tomato Tart

Caramelize the onions – Preheat an extra large skillet over medium low heat with a drizzle of olive oil. Add the sliced onions and a pinch of salt and cook down stirring often until caramelized, about 45 minutes.
Prepare the cashew ricotta – this is best done a day in advance so it can be completely chilled and thickened up.
Make the tart crust – add the flour to a mixing bowl and grate the chilled butter over the flour. Quickly work the butter into the flour until it resembles wet sand. Pour in the cold water and mix it in with a spoon until a dough is formed. Cut the dough in half and form two balls. Place each dough ball in between two pieces of parchment paper (aprox 16 inch square) and press it down into a disk. Use a rolling pin to go over the top and roll it out into 1/8 inch thick rounds. Refrigerate for about 20 minutes until it sets a bit.
Assemble the tart – place the tart with the parchment paper on top of a baking sheet. Start by spreading 1/4 cup or so of cashew ricotta over the bottom of each crust leaving one inch of space at the edges. Top with half of the caramelized onion and finish with a layer of tomato slices. Fold the edges over the pie patching it if it breaks. (Optional- brush the edges with some aquafaba or olive oil if desired).
Bake – Preheat your oven to 400″F and bake the tomato tarts for about 35 minutes or so until golden brown. Allow to cool off completely and serve.

Recipe Tips + FAQ

Make ahead – prepare the crust, cashew ricotta and caramelized onions a couple of days in advance and refrigerate until ready to bake. The pie crust can also be frozen and thawed out in the fridge the night before using it.
Storage – any leftovers can be refrigerated in lidded containers and enjoyed cold or reheated under the broiler or a toaster oven.
Topping ideas – grilled vegetables like bell peppers, zucchini rounds, basil pesto, vegan feta or mozzarella and fresh herbs like parsley and thyme. During fall and winter i’d swap the heirloom tomatoes for some roasted butternut squash alongside the caramelized onions and crispy sage.

Heirloom Tomato Recipes

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