This not quite a quiche because it has no eggs in it, but it's a quick little main dish pie to throw together.
1 box Stouffer's Spinach Souffle (thawed)
1/4 stick butter
1/2 large onion chopped
2 cups sliced fresh mushrooms
Salt, pepper, garlic powder to taste
6-8 slices Swiss cheese
1 9 inch pie crust (your favorite recipe, a frozen one, or already made)
Saute the onions and mushrooms in butter until soft. Add seasonings. Put about 3-4 slices Swiss cheese to cover the bottom of the pie crust. Add mushroom and onion mixture. Top with 3-4 more slices of Swiss cheese. Spread thawed spinach souffle over top. Bake at 400 degrees until crust is light brown (about 20-25 minutes).