1 box frozen perch or flounder fillets
1 med. onion, chopped
1 can cream of mushroom soup
1 (16 oz.) c. sour cream
1 c. grated cheddar cheese
Salt and pepper to taste

Preheat oven to 325 degrees. Mix mushroom soup and sour cream together. Place fillets in shallow baking pan. Cover with onions and grated cheese. Pour soup and sour cream mixture on top. Bake in 325 degree oven for 25 minutes. Serve hot.