Franklin's Homewood Gourmet Spinach & Mushroom Quiche

1 pie shell
1 box frozen spinach, thawed and liquid squeezed out
4 ounces sliced mushrooms
1/2 medium onion diced
2 tablespoons oil
3 eggs
1 cup cream
Salt, pepper, and nutmeg to taste
1 cup grated asiago or parmesan cheese

Pre-bake the pie shell and cool. Saut