Tarte a l'Oignon (French Onion Quiche)

Steps

1. Preheat oven to 400 degrees F.
2. Cut the bacon into 1" pieces and cook in a skillet and cook over medium heat until browned. Remove bacon from skillet, reserving 4 tablespoons bacon fat, and drain on paper towels.
3. Slice onions and place in the skillet with the bacon fat, and cook over medium-high heat until evenly browned, about 8 minutes. Season with salt and pepper.
4. Combine the milk and heavy cream in a bowl.
5. Sprinkle the all-purpose flour over the onions and stir to blend. Stir in the milk mixture.
6. Cook and stir over medium heat until the mixture thickens.
7. Remove from heat, stir in the bacon, and set aside to cool 10 minutes.
8. Beat the eggs in a mixing bowl until light colored and frothy.
9. Stir a spoonful of the onion mixture into the eggs. Add another spoonful of the onion mixture, and continue stirring. Repeat, until all the onions have been stirred into the eggs and are thoroughly blended. Pour the mixture into the prepared pie shell. Sprinkle with nutmeg.
10. Bake until the crust is lightly browned, about 20 minutes.
11. Remove from the oven and cool 5 minutes before serving.