Prepare the chiles: Remove the stems and seeds from the dried guajillo and ancho chiles. Toast them in a dry skillet over medium heat for 2-3 minutes until fragrant, but be careful not to burn them.
Blend the marinade: In a blender, combine the toasted chiles, chopped onion, minced garlic, cumin, oregano, salt, and pepper. Add 1 cup of broth and blend until smooth to create a marinade.
Marinate the beef: In a large bowl, coat the beef with the marinade, making sure it is evenly covered. Cover and refrigerate for at least 2 hours, preferably overnight for maximum flavor.
Cook the beef: Transfer the marinated beef to a slow cooker. Add the remaining broth and bay leaves. Cook on low for 6-8 hours or until the beef is tender and easily shreds with a fork.
Shred the meat: Once done, remove the beef from the slow cooker and let it rest for a few minutes. Shred the meat using two forks, discarding any excess fat.
Prepare the tortillas: While the beef is resting, warm the homemade corn tortillas on a skillet over medium heat until pliable.
Assemble the tacos: Place a generous amount of shredded beef in the center of each tortilla. Add chopped onions, cilantro, and a squeeze of lime for a fresh touch.
Serve: Serve the tacos immediately alongside the flavorful consomé for dipping and drizzle with spicy birria sauce for an extra kick.
