Toast the stemmed, seeded guajillo and ancho chiles in a dry pan over medium heat for a few seconds a side, just until they smell fragrant and turn slightly pliable. Pull them the moment the smell sharpens, since scorched chile turns the whole pot bitter. Cover them with hot water and soak until soft, about 20 minutes.
In the same dry pan, char the tomatoes, the halved onion and the garlic over high heat until blackened in patches.
Blend the softened chiles, the charred vegetables, the vinegar, cumin, oregano, cinnamon, cloves and salt with a cup of the beef broth until completely smooth. Pass the puree through a sieve if you want a silky consome.
Season the beef chunks with salt and sear them hard in the pot over high heat until browned on at least two sides, working in batches so the pan stays hot.
Return all the beef to the pot, pour in the chile puree and the remaining broth, add the bay leaves, and bring to a bare simmer. Cover and cook at the lowest steady simmer, or in a 300F oven, for about 3 hours, until the meat pulls apart with no resistance.
Lift the beef out and shred it. Let the broth settle, then skim the red fat from the surface into a small bowl and keep it. The remaining broth is the consome.
For each taco, dip a corn tortilla in the reserved red fat, lay it on a hot griddle, add shredded beef and cheese, fold, and fry until the tortilla is crisp and the cheese has melted. Serve with a cup of hot consome for dipping.