Molletes

A mollete is an open-faced sandwich with refried beans and white cheese in Mexican cuisine, served hot. The name may be related to the name for a certain type of Spanish bread. A mollete, native to Mexico City, is made with bolillos sliced lengthwise and partially hollowed, filled with refried beans, and topped with cheese and occasionally slices of jalapeño or serrano peppers. It is then grilled in an oven until the cheese melts. The refried beans are "frijol mantequilla" (literally, "butter beans") known outside of the region as "pinto beans".

Source: Wikipedia