Tomato Onion Tart

If you like savory tarts, you probably have your favorite. Is it Quiche Lorraine? Spinach and Mushroom, or maybe Potato and Leek? Well, whatever it is – it’s not really your favorite. Oh sure, you might think it is. But that’s just because you haven’t tried my Tomato Onion Tart. Trust me – it has no equals.

If there was ever a dish without a secret ingredient, this is it. It’s just Pâte Brisée (pie dough), filled with a layer of caramelized onions, a layer of grated gruyère, and a layer of halved cherry tomatoes arranged in snug circles. The cherry tomatoes burst with each bite like little balloons, their tartness balanced by jammy onions, and rounded with the richness of the cheese. No combination can be simpler or more sublime.

Even when tomatoes are not in season, this tart seems to bring out the best in them; I find it to be a perfect antidote to February grayness when comfort food is starting to get to me, yet summer is nowhere in site. Besides, it’s Jason’s favorite dish, on par with seared tuna and Boeuf Bourguignon, so making it only during the tomato season is not really an option (at least not for me ;)

Pâte Brisée (tart dough) for one 10-inch tart
3 Tbsp olive oil
1 Tbsp butter
1 and 1/2 Lb yellow onions, sliced
1 and 1/2 tsp salt
1 tsp balsamic vinegar (optional)
6 oz gruyère, grated
1 Lb cherry tomatoes, halved

1. Roll out the dough 1/8 inch thick. Fit into tart pan, trim, and chill 30 minutes while preparing the onions and preheating the oven.
2. Preheat the oven to 425F with racks in the bottom third and upper third of the oven. If you have a pizza stone, place it on the bottom rack.
3. Set a large, heavy pot oven medium heat. Add oil and butter. When butter is melted, add onions and salt. Cook stirring occasionally until onions are tender, about 12 minutes. Turn down the heat to medium-low and cook stirring occasionally until onions are medium brown, about 45 minutes. Add balsamic vinegar (optional), and cook stirring occasionally until onions are dark nutty brown, about 15 minutes. Take off heat and set aside.
4. Place the tart pan on a cookie sheet. Line the tart shell with parchment paper or foil and dry beans (or some other weigh) and bake in the bottom third of the oven for 18 minutes. Remove parchment paper with beans, lightly poke dough with a fork at 1/4 inch intervals to prevent it from puffing up, and return to the bottom third of the oven for 5 more minutes.
5. Turn down the oven to 375F.
6. Fill the tart shell with caramelized onions. Sprinkle with a layer of gruyère. Arrange cherry tomatoes cut side down in concentric circles starting with the outer circle and working your way in towards the center of the tart. Bake tart on the bottom rack for 15 minutes. Move tart to the top rack and bake until tomatoes are just starting to brown, 15 more minutes. Cool 10 minutes before serving.