Simple Quiche Lorraine

Preheat the oven to 450 degrees F (230 degrees C).

Place pie pastry into a 9-inch pie pan; line with a double layer of aluminum foil and a layer of pie weights or dried beans.

Bake in the preheated oven until golden on the edges, about 8 minutes. Carefully remove the foil and weights; continue baking until crust is set and dry, about 5 minutes more. Remove from the oven and reduce the temperature to 325 degrees F (165 degrees C).

While the crust is baking, cook bacon in a large skillet over medium-high heat until crisp, about 10 minutes. Transfer to a paper towel-lined plate and crumble when cool enough to handle. Drain all but 2 tablespoons drippings from the skillet.

Add onion to drippings in the skillet; cook and stir over medium heat until tender, about 5 minutes. Use a slotted spoon and transfer to a bowl.

Toss Swiss cheese and flour together in a small bowl. Whisk milk, eggs, and salt together in a large bowl, then stir in bacon and onion. Mix in cheese mixture until well combined, then pour into pie crust.

Bake in the preheated oven until a knife inserted into the center comes out clean, 35 to 40 minutes. If necessary, cover the edge of crust with foil while baking to prevent burning or over-browning. Let stand for 10 minutes before serving.