Remove stems and seeds from the guajillo and ancho chiles. Wipe the insides with a dry paper towel to remove loose seeds.

Place chiles in a bowl and pour hot (not boiling) water over them to cover. Let them soak for 15–20 minutes until softened.

Tip: For a deeper roast flavor, briefly char the chiles in a dry skillet or on a baking sheet under the broiler before soaking.

In a blender, combine the rehydrated chiles, a few tablespoons of the soaking liquid (not all), 1/2 the onion (rough-chopped), 2 garlic cloves, cumin, oregano, and a pinch of salt. Blend to a smooth paste.

In a large pot or Dutch oven, add the beef chuck roast, the remaining onion quarters, 2 garlic cloves, bay leaves, the chile paste, and 4 cups beef broth. Season lightly with salt and pepper.

Bring to a gentle boil, then reduce to low, cover, and simmer gently for 2–3 hours until the beef is fork-tender.

Tip: For an even richer flavor, sear the beef on all sides in a little neutral oil before adding the liquids.

When beef is tender, transfer it to a cutting board or tray. Use two forks to shred the meat into bite-sized pieces.

Strain the braising liquid through a fine-mesh sieve into a bowl or large measuring cup and reserve the liquid as your consomé for dipping.

Tip: Skim any excess fat from the top of the consomé if you prefer a lighter broth.

Heat a skillet or griddle over medium heat. Lightly toast corn tortillas one at a time for 10–20 seconds per side.

Spoon a generous amount of shredded beef onto each tortilla and sprinkle with Oaxacan cheese.

Tip: To avoid soggy tacos, don’t overfill; keep the tortilla warmed and slightly drier than wet before adding fillings.

Fold each filled tortilla in half and add a little oil to the skillet. Fry the folded taco until the outside is crisp and golden and the cheese inside has melted, about 1–2 minutes per side.

Tip: Use a heavy spatula and press gently to encourage even melting and crisping.

Plate the tacos and garnish with chopped onions, cilantro, and lime wedges. Serve with a small bowl of hot consomé alongside.

Serving tip: Add sliced avocado, pickled red onions, or a mild green salsa for freshness.