01 - In a small mixing bowl, combine ground cumin, dried oregano, smoked paprika, sea salt, black pepper, and cinnamon. Stir until evenly blended.
02 - Arrange the chuck roast chunks in the slow cooker. Sprinkle the spice blend over the beef and toss thoroughly to ensure each piece is evenly coated.
03 - Scatter the chopped onion, minced garlic, chopped chipotle peppers, and jalapeño over the seasoned beef in the slow cooker.
04 - In a separate bowl, whisk together the fresh lime juice, apple cider vinegar, beef broth, and tomato paste until smooth. Pour the mixture evenly over the beef and vegetables.
05 - 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 apart effortlessly.
06 - Discard the bay leaves. Using two forks, shred the beef directly in the slow cooker, mixing the shredded meat with the accumulated cooking juices until well combined.
07 - Serve the barbacoa hot in tacos, burritos, or over rice, accompanied by your favorite toppings such as fresh cilantro, diced onion, and lime wedges.