4 pounds split mackerel 5 tablespoons butter or margarine 1/2 cup onion, diced 1 tablespoon fresh parsley, finely chopped 1/4 pound fresh mushrooms, sliced 1 cup soft bread crumbs salt and pepper, to taste
Preheat oven to 350F. Wash fish and pat dry. Sprinkle inside and out with salt and pepper. Melt 3 tablespoons of butter in a skillet and cook onions, parsley and mushrooms until onion yellows. Add vegetables to bread crumbs and mix well, seasoning with salt and pepper to taste.
Stuff fish with the mixture and close with toothpicks or skewers, or sew closed with needle and thread. Place stuffed fish in a greased baking pan, making several slits in skin of fish. Melt remaining butter and brush on fish. Bake for 45 to 50 minutes or until fish flakes easily when tested.
Note: Any firm whole fish, such as rockfish or bluefish, can be substituted for mackerel.