2. In a large pot, add beef, beef broth, garlic, onion, vinegar, salt, pepper, oregano, cumin, bay leaves, guajillo chiles, ancho chiles, and cinnamon stick.
3. Bring to a boil, then reduce heat and simmer for 2.5 to 3 hours, until beef is tender.
4. Remove beef and shred with forks. Strain the broth and blend the solids until smooth. Return broth and beef to the pot.
5. Serve hot with tortillas, lime, and chopped onions.