01 - Toast dried guajillo, ancho, and pasilla chiles in a dry skillet over medium heat for 1 to 2 minutes until aromatic. Transfer to a bowl, cover with hot water, and soak for 15 minutes.
02 - In the same skillet, roast the quartered white onion, garlic cloves, and halved Roma tomatoes until charred, approximately 8 minutes.
03 - Drain soaked chiles and combine in a blender with roasted onion, garlic, tomatoes, cumin seeds, dried oregano, ground cinnamon, black peppercorns, cloves, and 1 cup beef broth. Blend until smooth.
04 - Place beef chuck and short ribs into the slow cooker. Pour chile sauce over the meat. Add bay leaves, kosher salt, apple cider vinegar, remaining beef broth, and water. Stir gently to mix.
05 - Cover and cook on low heat for 8 hours, until the beef is tender and shreds easily with a fork.
06 - Remove beef from slow cooker, shred with two forks, and discard bones. Skim fat from consommé; reserve some fat for frying. Strain consommé if desired and keep warm.
07 - Heat reserved fat or vegetable oil in a skillet over medium heat. Briefly dip each corn tortilla in warm consommé, then place on skillet. Optionally sprinkle with cheese, add shredded beef, and cook until tortillas are crisp and cheese melts. Fold tacos in half.
08 - Serve tacos garnished with diced white onion, chopped cilantro, and lime wedges. Accompany with a cup of hot consommé for dipping.