With a simple façade, the unassuming Fonda Margarita sits next to a carwash and wouldn’t attract much attention if it weren’t for the line out the door and around the block by the time it opens at 5:30 a.m. Construction workers come at the crack of dawn, office workers arrive in shifts and sleepy teenagers meander in just before they close at 11 a.m. “We’re traditional,” says owner Richard Castillo when we ask him why his restaurant, which only serves breakfast, is so popular, “and there aren’t many traditional places left in Mexico City. We still cook using clay pots and 100 percent coal-fired grills.”

Alex Montes and his business partner, Askari Mateos, have spent years fussing over their recipes for tlayudas: large, thin corn tortillas topped with various ingredients. So what is the secret to a great tlayuda? Montes thinks for a moment. “The asiento [the unrefined pork lard that covers the tortilla],” he finally says, “and the beans, always with avocado leaf.” “The great thing about a restaurant,” he continues, “[is that] you make the same dish over and over so you have endless chances to perfect it.” We’d say that Montes and Mateos have done just that – the Oaxacan food at Las Tlayudas, the duo’s restaurant in Colonia del Valle, is pretty much perfect.