Start by removing the stems and seeds of ancho and guajilo chilies, as well as chilies de arbol.
Season all the meat generously with salt.
Sear the meat in batches in a large oiled pot over medium heat, searing 2-3 minutes on all sides.
Saute chopped onions until softened, then add tomato paste and cook down.
Add sliced garlic and saute until fragrant, then add the rich beef stock and chilies.
Add the seared meat back into the pot.
In a cheesecloth, add black peppercorns, toasted coriander, cinnamon stick, and bay leaves, tying tightly.
Add the spice bag into the stock and bring to a light simmer, cover, and braise for 1 hour.
Remove the chilies, blend them with a little stock, then pour back into the stew and simmer for 90 minutes.
Remove the meat, shred using a fork, season the broth with salt, and set aside.
Dunk a fresh tortilla in the broth, then place in a skillet over medium heat.
Top with shredded Oaxaca cheese and cook until melted.
Add braised shredded meat and consomme, fold the taco, cook for 1-2 minutes on each side.
Serve with consomme topped with diced onions and chopped cilantro.