Preheat your oven to 350℉. Lightly coat a 9x13 baking dish with cooking spray.
Place a large skillet over medium-high heat. Add the meat and onion to the pan. Break up the meat with a spatula, then season it with Worcestershire sauce, salt, pepper, garlic powder, and onion powder. Cook for 5-7 minutes, stirring frequently, until the meat is cooked through and the onions are softened. Drain the fat, then set the meat aside.
Cut the rolls in half horizontally without separating them, and place the bottom half in a 9x13 baking dish.
Layer 6 slices of cheese on the bottom half of the rolls so they are slightly overlapping. Top with the browned meat and spread into an even layer. Then, add another layer of the remaining cheese and place the top half of the rolls on top.
Brush the tops of the rolls with melted butter and bake for 12 to 15 minutes until the cheese is melted and the buns are lightly browned.