Coat chicken with flour. Arrange chicken in single layer with skin down in melted butter in 13 x 9 x 2-inch baking dish. Bake uncovered in 425 degree oven for 30 minutes. Turn chicken, bake until brown, 15 to 20 minutes longer, until tender. Remove from oven and reduce temperature to 325 degrees. Pour off excess fat. Combine evaporated milk, soup, cheese, salt and pepper. Add onions and mushrooms to chicken. Pour soup mixture over chicken. Sprinkle with paprika. Cover dish with foil. Return to oven for 15 to 20 minutes.