1. Preheat oven to 350°F. Line a 9x9-inch or 9x13-inch pan with aluminum foil, spray with cooking spray; set aside.
2. Using a large serrated knife, slice the rolls in half so you have a top and bottom of the rolls. Do not separate rolls into individual pieces. Place the bottom of rolls in prepared pan.
3. Evenly layer about half of the ham over the rolls.
4. Evenly layer the cheese.
5. Evenly layer the remaining ham.
6. Add the top of rolls; set aside.
7. In a microwave-safe bowl, add the butter and heat on high power to melt, about 1 minute.
8. Add the mustard, poppy seeds, onion, Worcestershire sauce, salt, pepper, and whisk to combine.
9. Slowly pour the butter mixture over the rolls. Use a spatula or back of spoon to spread the mixture over the tops.
10. Cover with aluminum foil and allow rolls to stand at room temp for about 5 to 10 minutes.
11. Bake covered for about 20 minutes or until cheese has melted.
12. Lift foil and allow cooking for an additional 5 minutes, or until as done as desired. Slice sandwiches into individual servings and enjoy while still warm!