Preheat oven 375�F. Bake pie crust about 10 minutes or until bottom is slightly brown. Let cool.
Cook broccoli until tender; drain well.
Combine milk, eggs, margarine, flour, salt, pepper and 3/4 cup cheese; whisk until well blended.
Sprinkle remaining 1/4 cup of cheese over crust.
Layer broccoli and mushrooms on cheese, pour milk and egg mixture over all.
Bake at 375�F for 35 to 45 minutes or until a knife inserted in center comes out clean.