Heat a dry skillet over medium heat. Toast the guajillo, ancho, and chile de árbol for 15–20 seconds per side until fragrant.

Place the toasted chiles in a bowl and cover with hot water. Let soak for 10–15 minutes until softened.

Add the softened chiles to a blender along with the pineapple juice, apple cider vinegar, achiote seasoning, garlic, brown sugar, salt, oregano, cumin, black pepper, and oil. Blend until completely smooth.

Slice the pork shoulder into thin 1/4-inch slices.

Pour the marinade over the pork and toss until every piece is well coated. Cover and refrigerate for at least 4 hours, preferably overnight.

Place a thick pineapple round on the base of the trompo. Stack the marinated pork tightly, pressing down as you go. Top with another pineapple round.

Roast at 375°F until the pork is deeply caramelized and reaches an internal temperature of 195–205°F, about 2–3 hours depending on the size of the trompo.

Broil for the last 5–10 minutes to crisp the edges.

Slice thin pieces from the outside and serve on warm corn tortillas with diced onion, cilantro, lime wedges, and grilled pineapple.