Months ago, I promised the recipe for a superfast Onion and Gruyère Tart—a promise on which I am finally making good. Increasingly I find myself pulling dinner together at the eleventh hour, and puff pastry is my secret weapon. For this recipe, a quickie riff on Suzanne Goin’s Alsatian tart flambé, you basically need a sheet of puff pastry, a yellow onion, some creme fraîche, ricotta, Gruyère and some sort of fat—like bacon or chopped up olives. It takes about 10 minutes to assemble (the lion’s share of which is grating cheese/slicing onions), and another 20-25 to bake.
1 sheet frozen all-butter puff pastry, defrosted
2 egg yolks
2 tablespoons oilve oil
1 large yellow onion, thinly sliced
1 tablespoon fresh rosemary, chopped
1/4 cup pitted cured olives (substitute: bacon for more traditional tart)
1/2 cup fresh ricotta
1/4 cup crème fraîche
1 cup grated Gruyère
Preheat oven to 400 degrees. Unroll puff pastry sheet onto parchment-lined baking sheet.
Mix one egg yolk with 1/2 teaspoon of water and brush egg wash around borders.
Add 1 tablespoon olive oil to skillet, and heat over medium flame. Add onions and rosemary (and bacon if using), and cook until onions are tender, about five minutes. Remove from heat and set aside.
In a food processor, purée together ricotta, remaining egg yolk, remaining tablespoon of olive oil. Fold in crème fraîche and a pinch of salt and pepper. Spread mixture over puff pastry. Sprinkle Gruyère over ricotta mixture. Using a slotted spoon, top with onions mixture and sprinkle olives over, if using. Bake for 20-25 minutes, rotating baking sheet once, until cheese is bubbling and crust is golden.