A quesadilla is a traditional Mexican dish that consists of a tortilla filled with cheese and other ingredients such as beans, vegetables or meats. The filling is usually heated before being placed inside the tortilla, which is then folded in half to create a half-moon shape. The quesadilla is cooked on both sides until the cheese melts and the tortilla becomes crispy. It can be served as an appetizer or main course and is often accompanied by salsa or guacamole.