A cheese sandwich is a simple and popular lunch food that consists of two slices of bread with cheese in between. The type of cheese used can vary, but common choices include cheddar, Swiss or American. Some people may also add additional toppings such as lettuce, tomato, or condiments like mustard or mayo. Overall, a cheese sandwich is a quick and easy meal that provides protein and flavor from the cheese, along with some added nutrition from any vegetables or spreads included in the recipe.