Even though it is available year-round, in Puerto Rico pernil (slow-roasted pork) equals Christmas. No holiday party is complete without pernil and arroz con gandules. For me, pernil equals loud music and laughter. It means fighting for the “cuerito,” the crackling skin, and trying to sneak out before anyone notices it's missing. Pernil is one of the first things we want visitors to Puerto Rico to try because we believe it will change their lives.
Whisk together the cumin, garlic powder, onion powder, oregano, paprika, white pepper and salt in a medium bowl.
Place the pork shoulder skin-side up on a rimmed baking sheet and rub with oil until evenly coated. Flip the pork so it is skin-side down and apply half of the spice mixture to the meat, sides and skin, massaging to make sure it is completely seasoned. Flip the pork so it is skin-side up again and with a long sharp knife, make a cut under the skin between the fat and the meat, avoiding cutting into the meat. This will create a pocket between the skin and the meat.
Combine the remaining spice mixture with enough oil to create a paste. Using your fingers, season the inside of the pocket with the paste, avoiding the skin. Coat the bottom and sides of the pork with the paste, patting it in as needed and continuing to avoid the skin. Transfer the pork skin-side down to a large deep pan. Cover with plastic wrap and refrigerate for 1 day.
Remove the pork from the refrigerator at least 1 hour before roasting and bring to room temperature. Meanwhile, preheat the oven to 300 degrees F.
Transfer the pork skin-side down to a large roasting pan and roast until deep golden brown, about 2 hours. Flip the pork and continue roasting skin-side up until the meat shreds easily with a fork and an instant-read thermometer inserted in the center of the pork registers at least 165 degrees F, up to 3 hours more.
Allow the pork to rest in its juices, uncovered, for 1 hour.
Pull the pork into chunks with a fork and serve.
To avoid soggy skin, do not baste or cover the pork. For a “crackling” skin, mix equal parts salt and water in a spray bottle and spray the skin from time to time during the last hour of cooking.