In a medium skillet over medium-low heat, add roast beef and cover with a lid. Cook until warmed.
Meanwhile, in a small bowl, combine ketchup, garlic powder and onion powder. Spread on buns.
In a microwave safe bowl, add cheese and milk. Microwave in 20 second intervals until smooth and melted.
Place roast beef on the sauced buns and add cheese to each. Add top buns.
Serve with curly fries and refrigerate leftovers.
