Dough for single-crust deep-dish pie
1 package (12 ounces) thick-sliced bacon strips, coarsely chopped
3 large sweet onions, chopped
1 tablespoon minced fresh thyme
1/2 teaspoon coarsely ground pepper
1/8 teaspoon ground nutmeg
1-1/2 cups shredded Gruyere cheese
1/2 cup grated Parmesan cheese
8 large eggs, room temperature
2 cups whole milk
1 cup heavy whipping cream
On a lightly floured surface, roll dough to a 14-inch circle. Transfer to a 9-in. springform pan; press firmly against bottom and sides. Refrigerate while preparing filling.
In a large skillet, cook bacon over medium heat until crisp, stirring occasionally. Remove with a slotted spoon; drain on paper towels. Discard drippings, reserving 1 tablespoon in pan. Add onions to drippings; cook and stir over medium heat until caramelized, 20-25 minutes.
Stir in thyme, pepper and nutmeg; remove from the heat. Cool slightly. Stir in cheeses and reserved bacon; spoon into crust. Preheat oven to 350°. In a large bowl, whisk eggs, milk and cream until blended; pour over top. Place springform pan on a rimmed baking sheet.
Bake on a lower oven rack until a knife inserted near the center comes out clean, 75-85 minutes. Cool on a wire rack 15 minutes. Loosen sides from pan with a knife. Remove rim from pan.