4 to 5 cups reduced-sodium beef broth, divided
12 dried California or New Mexico chilies*, stemmed, seeded, and rinsed
1 large onion, cut into chunks
4 large garlic cloves
1 TBS ground cumin
1 tsp. dried Mexican oregano
1 boned, tied beef chuck roast (3 ½ to 4 lbs.) rinsed and patted dry
2 TBS olive oil
Bring 3 cups beef broth to a boil. Put chilies in a blender and pour boiling broth over them. Let stand, mixing occasionally, until chilies are limp, about 10 minutes. Add onion, garlic, and oregano and whirl until very smooth.
Meanwhile, preheat oven to 325F. Sprinkle beef all over with salt and pepper. Pour oil into a large heavy pot (not extremely wide) over medium-high heat. When hot, add roast and cook, turning as needed to brown all over, about 10 minutes total. Pour chile mixture over meat and add enough beef broth to come a third to half of the way up roast. Bring to a boil, cover pot, and transfer to oven.
Bake until beef is very tender when pierced, about 3 ½ hours, turning once. Transfer roast to a bowl. When cool enough to handle, remove string and pull meat into bite-size chunks, or shred as desired. Discard excess fat.
Meanwhile, skim fat from chile sauce in pot. Boil sauce over high heat, stirring often, until reduced to about 4 cups. Add salt and pepper to taste. Return beef to sauce and simmer until heated through. Serve in tortillas as burros or tacos, or in a bowl topped with cotija cheese and diced avocado. Serves 6. Takes about 5 hours from start to finish.
*I buy these in a bag at Food City. They are usually located with the other bagged spices, not in the spice aisle, closer to the produce section.