Preheat oven to 350 degrees
Place pie crust in a lightly greased pie pan.
In a large bowl, whisk eggs until light and fluffy.
Add milk, sour cream, onion, salt, pepper and mix until blended.
Layer grated cheeses in pie pan.
Pour egg mixture over cheese.
Sprinkle chopped bacon over top of quiche.
Bake in oven for 40 minutes.
Sprinkle Parmesan cheese over quiche and bake for another 5-8 minutes - checking for doneness. If crust gets too dark, cover with tin foil for remaining time.
Remove from oven and let rest for 10 minutes before serving.