The Comedor Tipica Oaxaqueña food stall in the Mercado 20 de Noviembre builds a textbook perfect tlayuda - like a Mexican pizza - on a large, crunchy, comal-grilled tortilla. It's smeared with fragrant lard and black bean paste, topped with lettuce, tomatoes, avocado, queso oaxaca, and slices of marinated and grilled beef ‘tasajo’. Smoky salsa is served on the side.