Combine mayonnaise, sour cream, onion and parsley; mix well. Shape meat into six oval patties. Broil on both sides to desired doneness. Season with salt and pepper. Top patties with sauce and cheese; broil until cheese is melted. Spread toast with margarine; top with lettuce, tomato and patties. Makes 6 servings. Typed in MMformat by cjhartlin@email. Msn. Com