Heat olive oil in a large skillet over medium-high heat, then wait until it shimmers. Season beef generously with salt and pepper and brown on all sides for about 8 minutes total, until deeply browned.

Remove stems and seeds from dried guajillo chiles and dried ancho chiles, then toast them in a dry pan for 1-2 minutes. Add beef broth, apple cider vinegar, garlic, cumin, oregano, cloves, cinnamon, and black pepper to a blender with the toasted chiles, then blend until smooth.

Place browned beef in a slow cooker and pour the chile mixture over the top, then add bay leaves. Cover and cook on low for 8 hours until the beef shreds easily with a fork.

Shred the meat directly in the slow cooker and stir until the strands are coated in the glossy mahogany sauce. Stir in juice of 2 limes, then let rest for 10 minutes before serving.

Serve the barbacoa warm as a taco filling with tortillas, onions, and cilantro.