In a bowl, combine mayonnaise, sour cream, corned beef, onion, parsley, 1 tablespoon dill and seasoned salt. Cover and refrigerate overnight. Trace the large shamrock pattern onto a piece of waxed paper; cut out. Place on loaf. Carefully cut out and removed shamrock; set aside. Hollow out loaf, leaving a 1/2-in. shell. Cut removed bread and cutout shamrock into cubes. Fill shell with dip; sprinkle with remaining dill. Serve with bread cubes, vegetables and crackers. Yield: 4 cups.