Cut the rolls in half and line the bottom of a baking pan with the bottoms of the rolls. Layer the ham slices, then cheese and place the top half back on.

Mix the butter, Worcester sauce, mustard, brown sugar and onion powder. Pour the whole works over the buns, drenching each one. Cover tightly and marinade for 4-24 hours.

Preheat the oven to 350 degrees. Bake for 15 minutes, uncovered, or until cheese is melted and bun tops are a bit golden.