Reuben Cheese is a combination of SWISS cheese, corned beef, sauerkraut, and Thousand Island dressing, all sandwiched between two slices of rye bread. It is a popular sandwich in the United States, especially in New York City. The origin of the Reuben sandwich is disputed, but it is believed to have been created in the early 20th century. The combination of flavors makes for a unique and delicious sandwich.