In a small mixing bowl, combine the 2 tbsp azúcar moreno, 1 tbsp pimentón, 1 tbsp sal kosher, 1 tsp pimienta negra, 1 tsp polvo de ajo, 1 tsp polvo de cebolla, dried mustard, and ½ tsp pimienta de cayena. Mix well until evenly blended.

Pat the 4 lb paleta de cerdo con hueso completely dry with paper towels. This helps the rub stick and promotes a better crust. Rub the spice mixture all over every surface of the paleta de cerdo con hueso, pressing it in firmly. For best results, do this the night before and refrigerate uncovered — but even 30 minutes at room temperature makes a difference.

Preheat your oven to 300°F. Heat the 1 tbsp aceite vegetal in a large Dutch oven over medium-high heat. Once shimmering, sear the 4 lb paleta de cerdo con hueso on all sides until deeply browned, about 3–4 minutes per side. Don't rush this step — the sear builds flavor. Remove the 4 lb paleta de cerdo con hueso and set aside.

Pour the ½ cup vinagre de sidra de manzana, ½ cup caldo de pollo, and 2 tbsp salsa Worcestershire into the Dutch oven. Scrape up any browned bits from the bottom with a wooden spoon — that's pure flavor. Return the seared 4 lb paleta de cerdo con hueso to the pot, fat-side up. Spoon half the salsa BBQ over the top of the paleta de cerdo con hueso.

Cover the Dutch oven tightly with its lid and transfer to the preheated oven. Braise for 7–8 hours, until the 4 lb paleta de cerdo con hueso is completely fall-apart tender and an internal thermometer reads at least 200°F. The bone should wiggle freely and pull out cleanly.

Carefully remove the 4 lb paleta de cerdo con hueso from the Dutch oven and place on a large cutting board. Let it rest for 15 minutes — this makes it easier to handle and juicier. Using two forks (or your hands with heat-safe gloves), shred the meat, discarding any large pieces of fat or the bone.

Skim any excess fat from the surface of the braising liquid in the pot. Return the shredded 4 lb paleta de cerdo con hueso to the pot and stir in the remaining half cup of salsa grill. Toss everything together so the 4 lb paleta de cerdo con hueso is coated and soaks up the juices. Taste and adjust seasoning with 1 tbsp sal kosher if needed.

While the 4 lb paleta de cerdo con hueso rests, make the coleslaw. In a large mixing bowl, whisk together the ½ cup mayonesa, ½ cup vinagre de sidra de manzana, 1 tbsp azúcar, 1 tsp semilla de apio, 1 tbsp sal kosher, and 1 tsp pimienta negra until smooth.

Add the shredded 4 cups repollo verde finamente, 1 cup repollo rojo finamente, and 1 cup zanahorias to the dressing. Toss well until everything is evenly coated. Taste and adjust seasoning. Refrigerate for at least 15 minutes before serving so the flavors meld and the slaw softens slightly.

Toast the 8 panecillos de brioche cut-side down in a dry skillet or under the broiler for 1–2 minutes until lightly golden. Pile a generous heap of pulled 4 lb paleta de cerdo con hueso onto the bottom bun, top with a big scoop of coleslaw, add 8 slices encurtidos de eneldo if using, and finish with extra 1 cup salsa BBQ. Add the top bun and serve immediately.