2-3 lb. halibut
1 can cream of mushroom soup
1 pt. sour cream
1/2 c. Cheddar cheese (cubed)
1/2 c. chopped onion
1/2 c. sliced mushrooms

Place halibut in 2 quart baking dish. Combine all other ingredients and pour over fish. Cover and bake at 350 degrees for 1 hour.