01 -
Place the chuck roast, Roma tomatoes, onion, garlic head, salt, and bay leaves in the slow cooker. Pour in the measured water. Cover and cook on high for 6 hours or on low for 8 hours.
02 -
While wearing gloves, use scissors to cut open the guajillo, ancho, and arbol chiles. Remove stems and seeds. Transfer chiles to a bowl and cover with boiling water. Soak for 20 minutes, weighing chiles down with a plate if needed.
03 -
Toast the whole cloves, cinnamon stick, Mexican oregano, cumin seeds, thyme leaves, black peppercorns, and bay leaves in a dry pan over medium-high heat for 1–2 minutes until fragrant, stirring frequently.
04 -
In the same pan, brown the 4 garlic cloves on all sides, then transfer them to a blender.
05 -
Transfer toasted spices to the blender. Add the soaked and drained chiles, 950 ml hot beef cooking liquid from the slow cooker, and the cooked tomatoes. Blend until completely smooth. Add white vinegar and initial salt, blending briefly to combine.
06 -
Pass the blended sauce through a fine mesh strainer, pressing with a spoon to extract as much liquid as possible. Discard solids.
07 -
When the beef is tender, remove it from the slow cooker. Discard onion and garlic head. Shred the beef into bite-sized pieces.
08 -
Stir the strained chile sauce into the broth in the slow cooker. Return the shredded beef to the pot and mix well. Continue cooking on high for 1 hour.
09 -
Serve the birria hot with chopped onion, cilantro, sliced radishes, and lime wedges. Enjoy with freshly warmed corn tortillas or as a filling for tacos, enchiladas, or quesadillas.