1. Mix breadcrumbs, broth, onion, parsley and salt. Add meat and mix well. 2. Broil patty 3 inches from heat for 5 minutes. Turn and broil 5 to 7 minutes more, or until meat is cooked through. 3. Stir together sour cream, mayonnaise, mustard and dill weed. Spoon sauce over burger. 4. Arrange on top of 1 leaf of lettuce.