Prepare pastry and preheat oven to 425 F.
Sprinkle bacon, cheese and onion in a pastry-lined pie plate.
Beat eggs slightly before mixing in remaining ingredients.
Pour egg mixture into pie plate.
Cook uncovered in oven for 15 minutes.
Reduce oven temperature to 300 F.
Cook uncovered until a knife inserted halfway between center and edge comes out clean, about 30 minutes longer.
Let stand 10 minutes before cutting.