The Sunday Morning Lorraine

Make the pastry dough. Whisk together the flour and salt in a large bowl. Add the cold butter cubes and toss to coat them in flour. Using a pastry cutter or your fingertips, work the butter into the flour until the mixture resembles coarse meal with some pea-sized butter pieces remaining. Those larger pieces are what create flakiness.

Combine the ice water and apple cider vinegar, then drizzle it over the flour mixture. Toss with a fork until the dough just begins to clump together. If it feels too dry, add ice water one teaspoon at a time. Gather the dough into a rough ball, flatten it into a disk, wrap tightly in plastic, and refrigerate for at least 1 hour or up to 2 days.

On a lightly floured surface, roll the chilled dough into a 13-inch round, about 1/8-inch thick. Carefully drape it into a 9-inch deep-dish pie plate or tart pan with a removable bottom. Press the dough into the corners without stretching it. Trim the overhang to about 1/2 inch, then fold it under and crimp decoratively. Prick the bottom all over with a fork and refrigerate the shell for 30 minutes.

Preheat the oven to 400 degrees F. Line the chilled crust with parchment paper and fill with dried beans or pie weights. Bake for 15 minutes. Remove the parchment and weights, then bake for 5 to 7 minutes more until the bottom looks dry and the edges are just beginning to turn golden. Remove from the oven and reduce the temperature to 350 degrees F.

While the crust blind-bakes, cook the bacon. Place the bacon pieces in a cold skillet over medium heat. Cook, stirring occasionally, until the fat renders and the bacon is golden and crisp but still has a slight chew, about 8 to 10 minutes. Transfer to a paper towel-lined plate using a slotted spoon.

Pour off all but 1 tablespoon of bacon fat from the skillet. Add the diced shallot and cook over medium-low heat until soft and translucent, about 3 minutes. Set aside.

In a large bowl, whisk together the eggs, heavy cream, whole milk, nutmeg, white pepper, and cayenne until completely smooth. Do not rush this step. The custard should be uniform with no streaks of egg white visible.

Scatter half of the grated Gruyere across the bottom of the par-baked crust. Spread the bacon and softened shallots evenly over the cheese. Top with the remaining Gruyere.

Place the quiche on a sheet pan (to catch any drips) on the oven rack, then carefully pour the custard over the filling. Pour slowly to avoid displacing the ingredients. Fill it as close to the rim as possible.

Bake at 350 degrees F for 35 to 40 minutes, until the custard is set around the edges but still has a gentle wobble in the center when you nudge the pan. The top should be lightly golden with a few spots of deeper color where the cheese peeked through.

Remove from the oven and let it rest on a wire rack for at least 20 minutes. The residual heat will finish setting the center. Sprinkle with fresh chives just before slicing and serving.