Tlayudas are oversize corn tortillas which are more leathery and have a longer shelf-life than normal corn tortillas, known as "blandas." The word tlayuda refers both to the tortilla itself and the prepared dish. When prepared, tlayudas are spread with rendered pork fat ("asiento") and black bean paste, then covered in quesillo and topped with veggies - either shredded cabbage or lettuce, tomato and avocado, and served with your choice of meat - tasajo (beef), cecina (pork) or chorizo (sausage).
When served as street food, tlayudas are usually folded over and grilled over hot coals. When served in a restaurant they are most often served open-faced as pictured above. Vegetarians should ask for a tlayuda sencilla sin asiento ("sen-see-yah sin ah-see-ehn-toe") to get one without meat or lard.
Sometimes called "Oaxacan pizzas," tlayudas are usually consumed in the evening or as a late-night snack. The most popular place to eat tlayudas in Oaxaca is called Tlayudas Libres on Libres street between Murguia and M.Bravo streets, open from 9 pm until the early hours of the morning.