In a bowl, combine melted butter, mustard, Worcestershire sauce, and garlic salt until well blended.  Allow to cool.  You want the butter mixture to stiffen up again to create a spread.

Spread butter mixture over cut side of buns and place on a baking sheet.

Top buns with shredded Swiss cheese followed by a sprinkle of dried parsley if desired.

Broil in the oven on the middle rack (this prevents burning).  Broil until cheese is melted and buns are lightly toasted (just a couple of minutes). Makes 8 servings.