Braised Birria

Preheat oven to 275 °F. Bring ancho chiles and 4 cups water to a boil over medium-high. Remove from heat and let cool. Meanwhile, toast peanuts on a rimmed baking sheet, tossing once, until golden brown, 15 –20 minutes. Let cool. Toast cumin seeds and peppercorns in a dry small skillet, tossing occasionally, until very fragrant, about 2 minutes. Let cool, then finely grind in spice mill or with mortar and pestle with garlic powder and cinnamon. Purée ancho chiles and soaking liquid, peanuts, spice mixture, and chocolate in a blender until smooth. Strain through a fine-mesh sieve into a Dutch oven or other large heavy pot, reserving any solids. Return solids in sieve to blender and add 3 cups water. Process until smooth and strain back into Dutch oven; discard any solids. Heat oil in a large skillet over medium-high. Season meat generously with salt. Cook, turning occasionally, until browned all over, 12 –15 minutes total. Carefully add meat to Dutch oven and add bay leaves. Bring liquid to a simmer over medium-high. As soon as it just begins to bubble, lower heat, cover pan tightly with foil, then lid. Braise meat until meat shrinks off of bones and is fork-tender, 3 –3 1/2 hours (check periodically to make sure liquid is at a gentle simmer). Meanwhile, purée chiles de árbol, tomatoes, broth, and oregano in a clean blender until smooth. Strain through clean sieve into a large saucepan and bring to a simmer over medium heat; cook 10 minutes to let flavors meld. Season with salt; keep sauce warm. Increase oven to 400 °F. Let meat cool, uncovered, in braising liquid 30 minutes. Transfer meat to a rimmed baking sheet and roast until edges begin to brown, 13 –17 minutes. Pull or slice meat into servings. Divide among shallow bowls along with tomato-chile sauce. Serve meat with onion, cilantro, lime wedges, and tortillas alongside.