Remove the stems and seeds from the guajillo and ancho chilies. Soak them in hot water for about 15 minutes until they soften.
In a blender, combine the soaked chilies, onion, garlic, cumin, oregano, cinnamon, black pepper, and salt. Add a splash of soaking water and blend until smooth.
Cooking
In a large pot, heat oil over medium-high heat. Add beef and sear until browned, about 5-7 minutes.
Pour the blended chili sauce over the seared meat, then add broth, vinegar, and bay leaf. Stir to combine.
Bring to a boil, then reduce heat to low. Cover and simmer for 2-3 hours, until meat is tender.
Shred the meat using two forks and return it to the pot.
Heat corn tortillas in a skillet until warm and pliable, about 30 seconds on each side.
Place a generous amount of birria meat on each tortilla and fold to form tacos.
Top with chopped onions and cilantro.
Serve with birria broth for dipping, lime wedges, and optional salsa.