Preheat oven to 375°
Place the bottom half of 12 rolls in a 9x13 pan. (You will need two 9 x 13 pans)
Place about 2 shaved slices of ham on each roll. Cut the cheese slices into 4 parts and place 2 small pieces on each sandwich.
Put the dinner roll tops on.
In a sauce pan mix butter, Worchestershire sauce, onion powder, garlic powder, and poppy seeds. Wait until all the butter is melted and then brush over the ham sandwiches.
Cover with foil and let sit in fridge for 1 hour or over night. (If you want to bake them right away, you can also.)
Bake for 15 minutes or until cheese is melted. Then serve.