Toast the chiles on the griddle for 2-3 minutes, turning frequently while making sure they do not burn. If they burn, discard the chiles and start again.
Once toasted, transfer to a heatproof bowl. Add 1 cup hot water and let the chiles soak for 5 minutes, or until pliable.
Seed and devein the chiles, saving the water. Don’t worry if some seeds remain.
Add the saved water, the chiles, garlic, oregano, thyme, clove, cinnamon, bouillon, laurel leaves (or bay leaves), salt and pepper in a blender and blend until smooth, then set aside.
In a large pot, heat two tablespoons oil, and salt and pepper to the beef.
Sear the beef on all sides. Once the meat is brown, transfer to the slow cooker.
Add the chile mixture from the blender, and add enough water to cover the meat.
Set slow cooker on low for 6-8 hours.
Once done, shred the beef.
Serve with diced onions, chopped cilantro, and tortillas.