01 - Spread the chopped onion and minced garlic evenly across the bottom of the slow cooker.
02 - Nestle the beef chuck pieces on top of the onion and garlic layer.
03 - In a small mixing bowl, combine the chopped chipotle peppers, lime juice, ground cumin, dried oregano, smoked paprika, salt, black pepper, apple cider vinegar, and beef broth. Stir until well blended.
04 - Pour the seasoning mixture evenly over the beef. Tuck the bay leaves into the liquid. Cover the slow cooker and cook on low for 8 hours, or until the beef is fork-tender and shreds effortlessly.
05 - Discard the bay leaves. Using two forks, shred the beef directly in the slow cooker, allowing it to absorb the cooking juices. Mix thoroughly to ensure even coating.
06 - Serve the barbacoa hot with warm tortillas, over steamed rice, in burritos, or in grain bowls.