Step 1

Preheat oven to 375 degrees F.

Step 2

Pierce bottom and sides of pie crust with a fork. Bake for 15 minutes. Transfer to a wire rack. Reduce oven temperature to 350 degrees.

Step 3

Meanwhile, cook bacon in a large skillet over medium-low heat, stirring occasionally, until crisp, 8 to 10 minutes. Remove to a clean plate with a slotted spoon. Add onion to the pan and cook, stirring occasionally, until tender, 4 to 6 minutes. Scrape the onion into the crust.

Step 4

Whisk eggs, milk, nutmeg, salt and pepper in a medium bowl. Sprinkle the bacon and half the Gruyère over the onion, then pour the egg mixture over the top. Sprinkle with the remaining cheese. Set the pan on a baking sheet.

Step 5

Bake the quiche until the top is golden brown and the filling is set, about 40 minutes. Let cool for 15 minutes before serving.