Preheat oven to 350 degrees. Slice rolls and lay the bottom halves in a 9-inch by 13-inch baking dish, which has been sprayed with non-stick cooking spray.

Slather each side of the rolls with the mustard, them layer a piece of ham and cheese on each bottom half. Cover with the tops.

Microwave butter and onion together in a microwave-safe bowl for 1-2 minutes, then add Worchestershire sauce and garlic powder; mix to combine. Pour or spoon the sauce over the tops of the sandwiches.

Cover the sandwiches with foil and let them sit for 10 minutes or so, then put them into the oven for 20-25 minutes. Take off the foil for the last 5 minutes of cooking.

*Recipe adapted from Cook's Country