Delicious (and parve!) mushroom-onion quiche

I adapted this from a terrific recipe by a woman named Judith Gellerstein on some Jewish-lady recipe-share, found here, but please try this. It is absolutely awesome. Just takes a while as you have to cook the mushrooms and onions for nearly an hour so they brown and caramelize properly.

Parve Mushroom Onion Quiche
3-4 medium onions
2 cans sliced mushrooms
1 stick margarine (I know, I know, gross, but delicious)
1/2 cup non-dairy creamer
2 eggs
2 tbs flour
salt and pepper (always makes me nervous when there are no amounts, since I tend to oversalt things, but do your best. Less is more, but salt really brings out the flavor here.)
1 deep-dish pie crust or 2 regular pie crusts

Saute onion and mushrooms in margarine until soft, brown and caramelized. Will smell very delicious. Add rest of ingredients, stir well, and pour into pie shells or shell. Bake in 375 degree oven for about an hour, or until crust is brown and it looks done.