All-purpose flour, for rolling
1 homemade or store-bought single-crust pie dough
1 tablespoon unsalted butter
2 cups medium diced yellow onion (from 1 large onion)
Coarse salt and ground pepper
6 large eggs
3/4 cup heavy cream
3/4 pound bacon, cooked and crumbled
1 cup shredded Gruyere cheese (4 ounces)