Cook the meat: In a large pot, add the beef, bay leaves, onion, garlic, and salt. Cover with water and bring to a boil. Lower the heat, cover, and simmer for about 1 hour or until the meat is tender enough to shred easily.(If you use an Instant Pot, select the Meat/Stew setting — it takes about 30 minutes.)Once cooked, shred the beef and save one and a half cup of the broth.
Prepare the guajillo sauce: Remove stems and seeds from the guajillo chiles. Soak them in hot water for 10 minutes or until they soften.Blend the softened chiles with one garlic clove, cumin, oregano, salt, and one and a half cup of the reserved beef broth. Blend until completely smooth. Strain the sauce to remove any bits of skin.
Cook the potatoes: In a hot pan, add one teaspoon of oil. Add the diced potatoes and a pinch of salt. Stir, cover, and let them cook until soft. If they start to dry out, add a splash of water.
Combine everything: Add the shredded beef to the pan with the potatoes. Pour in the guajillo sauce and stir well to coat everything evenly.Bring to a gentle boil, then reduce the heat and simmer for about 8 minutes so the flavors come together. Taste and adjust with more salt or cumin if needed.