1Saute onion in margarine until it is transluscent.
2Add broccoli and cook until thawed.
3Add remaining ingredients, except grated cheese. Cook until cheese is melted.
4Pour into a greased 9x13-inch casserole dish. Sprinkle grated cheese over top of casserole. Bake at 350 degrees for 15 minutes or until cheese is melted and casserole is hot and bubbly.
5I usually make the casserole the night before and let it sit covered in the refrigerator overnight before baking. If you do this, it takes more than 15 minutes to bake. Just bake it until the casserole is bubbling and the cheese on top is melted.