1 c. butter
2 med. onions, sliced
1 lb. fish fillets
3/4 c. mayonnaise
1 tsp. parsley, chopped
Juice of one whole lemon
1/4 c. grated Parmesan cheese

Melt butter in hot baking pan. Place sliced onions over bottom of pan in butter. Place fish over onions. Mix mayonnaise, parsley, lemon juice and cheese; spread over fish. Bake at 350 degrees for 25 minutes.