Line unpricked pastry shell with a double thickness layer of heavy-duty aluminum foil. Bake in a preheated oven at 450 degrees for 5 minutes; remove foil and bake for 5 additional minutes. Remove from oven and let cool.
Reduce oven temp. to 425 degrees. Sprinkle bacon, cheeses, and onion over crust. Beat eggs with whipping cream and stir in spices. Pour over bacon mixture in shell. Bake for 15 minutes.
Reduce heat again down to 300 degrees. Bake 30 minutes longer or until knife inserted near center comes out clean.