Preheat an outdoor grill for high heat. Lightly grease one side of a large piece of heavy foil.
Form ground beef chuck into a patty, and place in the center of the foil’s prepared side. Arrange potato, carrot and sweet onion around the beef. Top with butter. Salt and pepper to taste. Tightly seal the foil around the beef and vegetables.
Place the sealed foil packet on the prepared grill. Turning frequently, cook approximately 30 minutes, or to desired doneness.