Cheeseburger Loaf

In a saucepan over medium heat, cook beef and onion until meat is no longer pink; drain. Add soup, garlic salt, salt and pepper; simmer for 5 to 10 minutes. Meanwhile, slice the top third off the bread. Hollow out bottom half of loaf, leaving a 3/4-in shell (discard removed bread or save for another use). Spread butter on cut side of bread. Place loaf on a baking sheet and broil until lightly browned. Spoon beef mixture into shell; arrange cheese slices on top. Broil until cheese is melted, about 2-3 minutes. Replace bread top.