1 unbaked, deep-dish pie crust
2 tablespoons unsalted butter
2 large yellow onions, sliced
8 slices smoked bacon
8 large eggs
1-1/2 cups heavy cream or half-and-half
1/2 teaspoon salt
1/2 teaspoon black pepper
2 cups grated sharp cheddar cheese
Have ready a deep-dish quiche pan, preferably with a removable bottom. Roll out the pie crust dough into a round; It should be large enough to fit across the bottom and over the sides of the pan. Fit the dough into the pan, pressing it across the bottom and sides. Let the extra drape over the edges of the pan. Loosely cover the dough and place it in the fridge.
Heat a large skillet over medium-low heat. Add the butter to the pan. Once melted, add the sliced onions and stir to coat them in butter. Slowly cook the onions for 15-20 minutes, stirring occasionally, until they’re soft and deep brown. Remove them to a plate and hold them aside. Add the strips of bacon to the skillet and cook over medium heat, turning once, until they’re cooked through and crispy.
Use paper towels to pat the bacon strips dry, then chop into small pieces.
Preheat the oven to 400°F. Whisk together the eggs, cream (or half-and-half), salt and pepper in a large mixing bowl or 2-quart pitcher. Stir in the cooled onions, chopped bacon and shredded cheese until everything is thoroughly combined.
Take the pan with the quiche shell from the fridge and set it on a baking sheet. Roll a rolling pin across the top of the pan to cut off the excess dough. The shell should have a neat edge all the way around. Pour the quiche filling into the shell and use a spoon to spread the onions, bacon and cheese evenly throughout.
Loosely cover the top with a piece of aluminum foil and place the baking sheet with the quiche into the oven. The baking sheet will catch any grease or overflow.
Bake the quiche for about 40 minutes, then remove the foil. Bake for 15-20 minutes more until the top and crust are browned and it has little or no wobble.
Remove the pan to a cooling rack and let it rest for at least 10-15 minutes. Slip the outside of the pan off the quiche, then slice and serve.