Step 1

To make the rub: Mix together salt, ancho chile powder, guajillo chile powder, cumin, oregano, onion powder, garlic powder, chipotle powder, and ground cloves. Season beef shoulder roast liberally with rub all over.

Step 2

Fire up smoker or grill to 250°F, adding chunks of smoking wood chunks when at temperature. Place beef in smoker and smoke for 3 hours.

Step 3

To make the sauce: While the beef is in the smoker, toast chilies in a large dutch oven over medium heat until fragrant, turning with tongs occasionally. Transfer to a small saucepan and cover with 2 cups of chicken stock. Bring to a boil over high heat, then reduce to a simmer and cook until chiles are completely softened, about 15 minutes. Set aside.

Step 4

Heat 1 tablespoon oil in now-empty Dutch oven over high heat until shimmering. Cook oxtails until well-browned on all sides, about 8 minutes total. Remove oxtails and set aside. Reduce heat to medium.

Step 5

Heat remaining 2 tablespoons of oil in now empty dutch oven over high heat until shimmering. Add in onion and garlic and cook until well browned, about 10 minutes. Add in oregano, cumin, ground cloves, and cinnamon and cook until fragrant, about 30 seconds. Add in remaining 2 cups of chicken stock, vinegar, and chipotles and bring to a boil. Reduce heat to medium and simmer until liquid is reduced by half, about 20 minutes.

Step 6

Transfer entire contents of dutch oven to the jar of a blender, along with soaked chilies and their soaking liquid. Puree until completely smooth, about 1 minutes. Set aside.

Step 7

Transfer beef to now empty dutch oven. Pour sauce over beef and add in bay leaves. Place lid on dutch oven slightly cracked, then transfer to smoker or a 250°F oven. Continue to cook until a metal skewer can be inserted into the beef with little to no resistance, about 3 hours.

Step 8

Transfer beef to a plate and discard bay leaves. Return dutch oven to stovetop and cook sauce over medium-high heat until reduced by half, about 5 minutes, skimming off any excess fat from surface. Stir lime juice into sauce.

Step 9

Meat can be pulled and returned to sauce for immediate serving, but for best flavor and tenderness, place beef in a large bowl and cover with reduced sauce. Refrigerate overnight or up to five days. When ready to serve, remove beef from liquid and cut into 1/2-inch slices. Place sauce and beef slices into dutch oven a bring to a simmer over medium heat. Gently fold beef until warmed through, thoroughly coated with sauce, and broken down into small pieces. Season with salt to taste. Serve on toasted corn or flour tortillas with onion, cilantro, tomatillo salsa, and lime.