Carmelized Onion Tarts
This is our interpretation of the classic French pissaladière. Ours is both easier to make and easier to pronounce.
For the tart crusts
1 package frozen puff pastry (2 sheets), thawed according to package directions
For the topping
2 tablespoons olive oil
Prepare the tart crusts
Unfold the pastry sheets and cut each one along the fold lines, creating three tarts from each sheet, each about 3 inches wide. (Work with one sheet at a time, keeping the second sheet chilled, covered with plastic wrap). Fold up about 1/2 inch of the edge of each tart to create a “crust.” Brush the entire tart with egg wash and prick the dough all over with the tines of a fork. Cover and refrigerate the uncooked tarts for 20 minutes, until firm.
Prepare the topping
Heat the olive oil in a large saucepan over medium heat. Add the onions and salt. Cook, stirring occasionally, until the onions are golden in color and soft, 30 to 40 minutes.
The tarts without toppings can be made up to 2 days ahead and kept tightly covered at room temperature. The onions can be cooked 3 to 4 days ahead and kept covered and refrigerated. Assemble the tarts no more than 3 hours before the party and warm them on a baking sheet in a 400°F oven for 8 to 10 minutes.