This classic Quiche Lorraine—perfect for brunch, lunch, or even dinner—combines lean bacon, leeks, and aged Comté cheese in a buttery homemade crust. Chef Boulud also adds endives for a slight bitter note that balances the sweet richness of the other ingredients. This recipe is a real skill-sharpener that'll produce very impressive results!
Make crust: In a stand mixer fitted with a paddle attachment, add flour, butter, and salt. Mix at lowest speed until mixture resembles coarse cornmeal. With the motor still running, slowly add egg yolks one at a time, then the cold water; continue mixing until the dough comes together, 10–15 seconds. Turn dough onto a flat work surface and bring it together with your hands. Dust surface and dough with flour, then shape into a disk about 8 inches in diameter and ½ inch thick. (Optional: Use a rolling pin dusted with flour to help you flatten the dough.) Wrap disk in plastic and refrigerate for 2 hours and up to overnight. (Dough can be stored in the refrigerator for up to 2 days or in the freezer for up to 2 weeks; defrost in the refrigerator before continuing with recipe.)
Shape dough: Preheat the oven to 325 degrees F. Remove dough from refrigerator. Use a pastry brush to grease the bottom and sides of the tart pan with softened butter.Unwrap the dough and place on a lightly floured work surface. Use a rolling pin to flatten the dough into a circle; every few rolls, rotate the dough a quarter-turn to even out the thickness and shape, dusting with flour as needed. Center the tart pan on the circle of dough: the dough should extend at least 2 inches past the edge of the pan, all the way around, in order to line the walls of the tart pan. Transfer dough to tart pan: Gently fold dough in half, then in half again. Center the tip of dough wedge in the middle of the pan and gently unfold. Use your fingers to ease the dough against the sides of the pan and help it lie flat against the bottom; avoid stretching or tearing. Leaving a ¼-inch overhang, trim the excess dough with a paring knife. Shape excess dough into a ball and use it to push the dough into the fluted walls of the pan. Fold and press the overhanging dough over the rim; this will help the dough hold its shape as it bakes.
Parbake crust: Line dough with a circle of parchment paper; fill pan with baking beans or pie weights. Bake for 20–25 minutes. Meanwhile, make an egg wash by whisking an egg with a tablespoon of water. Set aside. After 20–25 minutes, remove parbaked crust from oven; remove the parchment paper and baking beans. Use a serrated knife to trim away the crust along the top of the tart pan so it's flush with the edge; now that the dough is partially cooked, it won’t shrink as it cooks further. Brush the bottom and sides with the egg wash and place back in the oven, 5 more minutes. Crust is parbaked when it’s firm but hasn't taken on color; the sides should be pulling away slightly from the pan. Set aside to cool. Increase oven temperature to 350 degrees F.
Filling: Trim root end of the leeks. Slice in half lengthwise, then slice into ¼-inch half-moons. Trim root end of the endives, then remove outer leaves. Slice in half lengthwise, then slice into ¼-inch half-moons. Slice bacon into ¼-inch strips (or "lardons"). In a large sauté pan set over medium-low heat, melt the butter. Add bacon, leeks, endives, a few turns of pepper, and a pinch of salt. Stir and sweat until vegetables are soft but not brown, 8–10 minutes. Towards the end of cooking, turn heat to low and add chopped garlic. Stir to combine, turn off heat, and set aside.
Custard: In large bowl, add eggs, egg yolks, salt, and pepper; whisk together. Then slowly add cream while whisking; continue whisking until smooth. Set aside. Dice cheese into ½-inch cubes. Set aside.Assemble quiche: Place tart pan on a wire rack fitted into a rimmed baking sheet lined with parchment paper. Spoon the vegetable-bacon mixture into the tart crust and spread in an even layer; top with diced cheese. Mince about 2 tablespoons of chives and set aside. Ladle custard into the tart pan until it covers the filling and almost reaches the top. Gently shake the pan to settle the custard and eliminate air pockets. Pour remaining custard (about ¼–½ cup) into a measuring cup or small pitcher. Sprinkle quiche with half the minced chives, reserving the rest for garnish. Place quiche on oven rack; then add enough remaining custard to fill the crust to the very top without overflowing. Bake for 20 minutes. (Total baking time will be 50 minutes.)
After 20 minutes, rotate the pan 180 degrees and lower the temperature to 275 degrees F. Continue cooking until custard is set, another 25–30 minutes. Turn on broiler. Place quiche on a rack about 6 inches from heat source. Broil until top is a light golden brown, 1–2 minutes. Note: Keep an eye on it the entire time to prevent burning!
Remove quiche from oven and let cool in the pan, at least 30 minutes. Before serving, lightly brush top with olive oil. Remove tart ring. If you want to remove the bottom of the tart pan, gently run a knife between it and the crust before sliding it out. Garnish with reserved chives (optional). Serve warm or at room temperature. (To reheat a cold quiche: Bake at 200 degrees F for 20 minutes.)