Hailing from Oaxaca’s central valley, the tlayuda is an iconic street food staple that shines as a shared plate. The classic preparation, which you can find in any market in Oaxaca, at any food stall or in most restaurants, includes thin, large – about 16 inches – corn tortillas, which are grilled over hot coals, until crispy. To start, a layer of pork fat (asiento) and refried black beans is slathered on, serving as the base. Toppings are then added, in the form of shredded cabbage, onions, avocado, cheese (preferably quesillo), cilantro, thin slices of beef (tasajo), chicken (tinga) or pork (cecina), chiles, or chorizo. If this sounds like a pizza, you’re not far off: it’s often referred to as “Mexican pizza” by both Mexicans and foreigners alike. As an added bonus, it feels a bit healthier than pizza does, even if it isn’t. We’ll credit the cabbage for that.

Many claim Oaxacan food is the heart and soul of Mexican cooking, owing its diversity and quality to a plethora of enduring pre and post-Columbian recipes and techniques. To see this in action, one needn’t look further than Netflix. The latest season of its hit series Chef’s Table features Mexican chef Enrique Olvera; his episode is basically a love letter to the southern state. While fine dining has taken off in Oaxaca city, street food and traditional home cooking is still the raison d’etre, drawing in tourists from all over the world and paying homage to a storied and vibrant local culture.

Traditionally, the word tlayuda referred to the extra-large tortilla. They’re usually made by hand, using masa, pressed by hand, and then cooked over a comal, which is no small task. This requires hours of back-bending work grinding corn and a lot of hand-slapping. The tlayuda is then placed in a basket, where it will be encased with palm leaves. The steaming effect gives the tlayuda its unique texture: crunchy but pliable, with a distinct char. Over time, the moniker became synonymous with the street food favorite that exists today, though walking through a market to a chorus of “Tlayudas!” will likely yield just a stack of tortillas for sale if not also accompanied by the smell of cooking tasajo.

You can eat a tlayuda flat and open-faced by cutting up slices with a fork and knife. Though, thanks to its steam session in the banana-leaf lined basket, it’s also a prime candidate for folding. This portable option undoubtedly contributed to the tlayuda’s popularity on the late night circuit, which is where it reigns supreme.

The tlayuda’s origins are hard to track down. When pressed, most of the answers I received about the tlayuda’s history were vague including, “I don’t know, but it’s really old, por cierto” and “I think it might be pre-Hispanic.” Most seem satisfied with knowing that it’s delicious, it’s been around for awhile and it isn’t going anywhere, judging by its ubiquity. According to several Zapotec and Mixtec hawkers in Oaxaca’s Mercado de la Central de Abastos, the running theory is that convenience, a natural piling-on of common ingredients and the typical use of tortilla-as-vessel all conspired to make the ultimate midnight snack.

Without a doubt, though, its origins are long-standing and humble. The Florentine Codex, an ethnographic research account about life in Mesoamerica compiled in the 16th century by Spanish Franciscan monks, depicted women rolling masa into tortillas and even folding them, brimming with various ingredients. Culinary historian, founder of Princeton Cooking School, International Association of Culinary Professionals (IACP) member and food tour operator Ruth Alegria posits, “The process of preparation indicates, to me, that they were prepared to conserve them for use over long period of time. That is, the double process of cooking over a comal and then drying them further over a grill makes them almost cracker like in texture, albeit a very thin cracker, which can be stored without their deterioration.” Today, while enjoying the simple deliciousness of a tlayuda, it’s not hard to imagine that its roots go deeper than a stop on the way home from the bar.

We checked in with Mexico’s current Top Chef winner, Chef Rodolfo Castellanos, to get his expertise on the best preparation with a creative twist. Castellanos has a restaurant in Oaxaca city called Origen, which operates as a testament to his love for Oaxaca, the freshness of its local ingredients, the vibrancy of its food stalls, and its rich culinary history. Oaxaca pulls its dishes from both land and sea, so it only makes sense that Castellanos favors a tlayuda preparation that features octopus and sweetbreads.