After the quiche is cooked and set, the drizzle of syrupy reduced balsamic vinegar wakes up all the flavors with its sweetness and acidity. The quiche needs to rest for a few minutes before you cut it into slices like a pie, but don’t let it rest too long—it’s still best when it is warm from the oven.
8tbsp(1 stick) unsalted butter, cubed and chilledplus 1 tbsp at room temperature for greasing the pie plate
8ozslab bacontrimmed and cut into ¼-inch-thick by 1-inch-long lardons
8ozcream cheese at room temperature
½tspground nutmeg(preferably freshly grated)
1½cupcoarsely grated Gruyère cheese
½cupfinely grated Parmesan cheese
MAKE THE DOUGH:
In a food processor fitted with the metal blade, pulse the flour and salt to blend. Pulse in the egg yolks and chilled butter until the mixture resembles coarse crumbs. Do not overmix. Pulse in 2 tablespoons of the ice water through the lid until the dough comes together and forms a rough ball. If it seems dry or loose, pulse in the remaining tablespoon ice water. Transfer the dough to a sheet of plastic wrap and press it into a flattened ball. Wrap in the plastic and refrigerate for 30 minutes. Preheat the oven to 400°F.
ROLL THE DOUGH AND PREBAKE THE THE PIE CRUST:
Grease the bottom and sides of a 9-inch pie plate with the softened butter and set the plate aside. Turn the dough out onto a lightly floured surface. Sprinkle the top of the dough with flour and use a rolling pin to roll it into a round that is 11 to 12 inches in diameter, adding more flour beneath the dough as needed to prevent it from sticking. Roll the dough up around the pin and transfer it to the prepared pie plate, pressing it gently into the bottom and up the sides. Ideally, there will be about 1 inch of excess dough hanging over the edges. Pinch the excess dough to create a “crimped” top edge. Place a sheet of parchment over the dough and fill with pie weights (dried beans work, too), place it in the oven, and bake for 12 to 15 minutes. Remove the weights and return the pie crust to the oven to bake until the dough turns light brown and firms up, 10 to 12 minutes more. Remove from the oven and let the crust cool completely.
COOK THE BACON:
Arrange the bacon lardons in a single layer in a medium skillet, add ¼ cup of water, and cook over low heat until the water cooks out and the bacon is crisp, 10 to 12 minutes. Remove the bacon with a slotted spoon and drain it on a plate lined with paper towels. Reserve the bacon fat.
MAKE THE FILLING:
In a large bowl, whisk together the eggs, cream cheese, milk, nutmeg, salt, Tabasco, and Worcestershire. Stir in both cheeses and 2 tablespoons of the reserved bacon fat.
BAKE THE QUICHE:
Sprinkle half of the crisped bacon lardons over the bottom of the cooled pie crust. Pour the filling into the crust and top with the remaining bacon. Bake the quiche until the filling sets and browns on top, 25 to 30 minutes. Remove it from the oven and set it aside to cool for 10 to 15 minutes.
REDUCE THE VINEGAR AND SERVE:
While the quiche is cooling, pour the vinegar into a small saucepan set over low heat. Simmer the vinegar until it has reduced by half, 5 to 8 minutes. It should be slightly syrupy. Transfer the reduced vinegar to a small bowl. Slice the quiche and serve each slice drizzled with a little of the reduced balsamic.