Prepare the Pork: Place the pork shoulder on a cutting board or in a large bowl.

Make Incisions: Using a 1-inch knife, stab the pork shoulder, creating deep holes.

First Night Marinade: In a large bowl, combine vinegar, lime juice, lemon juice, cilantro, oregano, and smashed garlic cloves.

Soak the Pork: Submerge the pork shoulder in the marinade and let it soak overnight (or for at least 4 hours).

Second Night Rinse: Rinse off the marinade from the pork shoulder.

Prepare Under-Skin Cavities (Optional): Carefully cut under the skin of the pork shoulder to create pockets for seasoning.

Make the Paste: In a bowl, mix minced garlic, minced cilantro, lemon juice, lime juice, olive oil, sazon with annatto, adobo, salt, and pepper to create a thick paste.

Season the Pork: Generously rub the paste all over the pork shoulder, ensuring it fills the holes made earlier and any cavities created under the skin.

Rest: Place the seasoned pork shoulder in a roasting pan and cover with aluminum foil. Let it rest overnight (or for at least 4 hours).

Preheat Oven: Preheat the oven to 400°F (200°C).

Initial Roast: Place the uncovered pork shoulder in the preheated oven for 20 minutes.

Reduce Heat: Cover the pork shoulder with aluminum foil and reduce the oven temperature to either 275°F (135°C) for a long roast or 350°F (175°C) for a shorter roast.

Slow Roast: Roast for 6-8 hours at 275°F (135°C) or 2-4 hours at 350°F (175°C) until the internal temperature reaches 160-170°F (71-77°C).

Crisp the Skin: Uncover the pork shoulder and increase the oven temperature back to 400°F (200°C). Roast for another 20 minutes, or until the skin is crispy.

Rest: Let the cooked pernil rest for 20 minutes before carving and serving.