Bring a small pot of water to near-boil. Submerge guajillo and ancho chiles for 10 minutes until pliable. Drain.

On a comal or skillet, roast the tomatoes, quartered onion, and garlic cloves (unpeeled) over medium-high heat until they blister and show golden spots. Turn to char evenly.

Peel garlic, then add tomatoes, onion, hydrated chiles, chipotle (if using), vinegar, cumin, oregano, and chicken stock to a blender. Blend until smooth. Taste and season with salt and pepper.

Heat oil in a large heavy pot or deep skillet over medium-high. Season chicken with salt and pepper. Sear pieces 3–4 minutes per side until golden; don’t fully cook through. Remove and set aside.

Pour the blended sauce into the pot. Add bay leaves. Return chicken to the sauce, nestling pieces so they’re partially covered. Add a splash more stock if needed.

Reduce heat to medium-low, cover, and simmer 30–40 minutes until chicken is cooked through and tender.

For shredded chicken, remove pieces, shred with two forks, then return meat to the pot to soak for 5–10 minutes. Adjust salt, pepper, and vinegar to taste.