A cheeseburger is a hamburger topped with cheese. Traditionally, the slice of cheese is placed on top of the meat patty. The cheese is usually added to the cooking hamburger patty shortly before serving, which allows the cheese to melt. Cheeseburgers can include variations in structure, ingredients and composition. The cheeseburger was invented by Lionel Sternberger one day in 1924, when Lionel put a slice of American cheese on one of his father's hamburgers.