Precaliente el horno a 350 grados F.
Remove the pernil and skin from the refrigerator. Use a paper towel to dry off any moisture on the skin.
Allow the pernil and skin to sit on the counter for at least 30 minutes before placing in the oven. A cold pernil will take longer to begin roasting.
Add about 1/2 cup of warm broth to the pan with the pernil in it. This will help get the juices going and keep the pernil moist.
Add a light sprinkle of salt over the pernil. Pork shoulder sweats out a lot of salt so we want to add a little more before it goes in the oven.
Cover the roasting pan with the pernil in it with aluminum foil. Do not cover the roasting pan with the skin in it.
Place the pernil and the skin in the oven. The two roasting pans should be side by side.
The skin should cook for about 2 hours. Cook the pernil for about 6 hours.
After 2 hours, check the skin to see if it's crispy. If so, remove from the oven. If not, pat it dry with a paper towel and continue cooking until it's crispy. Check on it every 5-10 minutes, to make sure it doesn't burn. You can rotate the pan and also brush the top with its drippings to help crisp it up. Once removed from the oven, it will continue to crisp as it cools.
Once you have removed the skin from the oven, continue cooking the pernil until it is fully cooked through, about 5 1/2 to 6 hours of cooking time depending on its size. 30-60 minutes before cooking time ends, remove the foil from the pan, baste the pernil, and continue cooking the pernil uncovered to allow it to brown. Check on it every 10 minutes to make sure it doesn't burn.
Remove the pernil from the oven and allow it to cool for at least 30 minutes in order to allow the internal juices to settle and lock in the moisture.
Then, place the pernil in a clean pan and shred the meat from the bone. Use a ladle to pour some of the drippings over the meat to keep it most and add flavor. (If there is a lot of grease in the drippings, use a large kitchen spoon to skim off some of the excess grease.)
Serve with your favorite sides, like arroz con gandules, ensalada de papa, and guineos en escabeche. Enjoy! ¡Buen provecho!