One of the great French classics, this onion tart is a favorite bistro dish in Paris and Lyon.
- Savory Tart Crust
- All Purpose Flour - 1 1/2 cup, unbleached
- Salt - 1/4 teaspoon
- Unsalted Butter - 3/4 cup (1-1/2 sticks), at room temperature. Cut into pieces
- Water - 1/4 to 1/3 cup
- Onion Filling
- Bacon - 3/4 cup, cut in 1/4-inch pieces (6 to 8 slices)
- Onion - 3 cups thinly sliced (about 2 medium-large onions)
- Cheese - 1/2 cup (2 ounces) finely diced to grated
- Egg Yolk - 1
- Heavy (whipping) cream - 1/2 cup
- Salt - 1 teaspoon
- Ground white pepper - 1/2 teaspoon
- Ground Nutmeg - Pinch
- Parsley - 6 sprigs for garnish (optional)
To make the crust: Combine the flour and salt in the large bowl of a heavy-duty electric mixer fitted with a paddle. With the mixer running on the slowest speed, add the butter and continue to mix until mixture resembles a coarse meal and the butter is completely incorporated into the flour, about 20 minutes. Increase the speed to medium and gradually add the water until the dough sticks together and no dry flour is visible. Do not overwork the dough. Or, to make by hand, cut the butter into the flour and salt with a pastry blender or 2 forks until the mixture resembles coarse meal. Gradually mix in the water with a fork until the dough pulls together into a ball.
Shape the dough into a compact ball, wrap in a cloth or plastic wrap, and let sit for at least 30 minutes at room temperature. The dough can be made 1 day ahead.
Preheat the oven to 350 F. On a floured board, using a floured rolling pin, roll the dough into a thin 12-inch circle. Fold the dough in half, then into quarters, transfer it to a 10-inch tart pan, and unfold it. Press the dough into the sides and bottom of the pan and roll a rolling pin over the top, cutting off the excess from the edges. Cut a piece of parchment paper or aluminum foil into a 1-inch circle. Place the paper or foil over the dough and fill with dried beans or pie weights.
Bake for about 30 minutes, or until the crust is set nd the edges are lightly browned. Carefully remove the beans and paper or foil. Return to the oven and bake the crust another 1 or 2 minutes, or until the dough is golden brown. Let cool slightly before filling.
To make the filling: In a 12-inch saute pan or skillet over medium-high heat, cook the bacon just until the fat begins to melt. Add the onions and continue to cook, stirring or shaking the pan, until they are golden in color, about 15 to 20 minutes. As they begin to brown, reduce the heat and stir more frequently to make sure the onions do not burn. Drain the onions in a colander. Let cool slightly.
In a large bowl, whisk together the egg yolk, cream, salt, pepper, and nutmeg. Add the cheese and onions. Fill the shell with the mixture, smoothing it evenly with a rubber spatula. Bake for 18 to 20 minutes, or until set and golden brown. Let cool slightly before cutting into wedges.
To serve: Place 1 wedge on each serving plate and garnish with a sprig of parsley.