Hawaiian Ham Sandwiches

My family L.O.V.E.S. this recipe from my mother-in-law:

24 Hawaiian rolls cut almost in half
12 slices ham (quartered)
8 slices Swiss cheese (cut in thirds)
 
Place a slice of cheese between 2 pieces of ham and place on roll.   
Place on a Pammed baking sheet.
 
1 stick butter (melted)
1T mustard
1T finely minced onions
1T poppy seed
1t Worcestershire sauce
 
Combine remaining ingredients and spoon over sandwiches.  Bake  at  
350• for 15 minutes.