From an uncomfortably cramped south Austin food trailer, Gerardo “Jerry” Guerrero prepares hearty yet tender portions of meat drowned in brisket broth. Alongside five of his family members — including his mother-in-law and his own mother — the owner of La Tunita 512 crafts a glistening crimson jewel of a taco that tastes as good as it looks. These crunchy vessels of chopped, guajillo chile-stained Texas beef are known as quesabirria de res tacos, or red tacos. Guerrero’s tacos are also served Costra-style, a novel Mexico City preparation method that upgrades a plain tortilla with a crisp, structurally sound round of griddled Monterey Jack. As the shredded cheese melts on the truck’s plancha, the taquero fishes out brisket chunks daubed in chile from a bubbling stockpot, vigorously chopping the protein. Folded together with diced onions and cilantro, this taco’s crunchy-on-the-outside-gooey-on-the-inside shell boasts a roastiness akin to a Cheez-It cracker, one that’s teased out further by the brisket’s fatty warmth. Finally, after a sharp squiggle of red salsa de arbol, the customer finishes the experience by dunking the taco head-first into a cup of lip-tingling consomme (beef broth).