Step 1

Purée tomatoes, onion, Cubanelle peppers, bell pepper, cilantro, and garlic in a food processor until smooth. Scoop out ½ cup soffritto and set aside. Reserve remaining soffritto for another use (you can use it for the arroz con gandules).

Step 2

Do Ahead: Soffritto can be made 3 days ahead. Transfer to an airtight container, cover, and chill, or freeze up to 3 months.

Step 3

Finely grind peppercorns in spice mill or with mortar and pestle. Transfer to a food processor. Add garlic, Sazón, salt, oregano, vinegar, 2 Tbsp. oil, and reserved ½ cup soffritto and purée until smooth.

Step 4

Push a small paring knife (about 3½" long) into pork through the skin, working the blade all the way in; twist knife to make a small hole in the meat. Repeat, making holes spaced about 1½" apart on all sides of pork.

Step 5

Rub pork all over with adobo mixture, pushing into holes and covering any exposed meat and skin. Try to get as much adobo mixture into meat and not just on the surface, where it may burn when roasting. Be sure to use all of it! Wrap pork tightly and chill at least 3 hours and up to 3 days.

Step 6

Place a rack in lower third of oven; preheat to 300°. Line a large roasting pan with 2 layers of heavy-duty foil. Place a roasting rack on top. Set pork, skin side up, on rack. Scrape any adobo mixture off skin and thoroughly pat dry with paper towels. Liberally brush cleaned skin with oil. Transfer pan to oven and carefully pour 2 cups water into pan. Roast pork until an instant-read thermometer inserted into thickest part of shoulder registers 180°, meat is pulling away from bone, and skin is crisp, 5–6 hours.

Step 7

Let pork sit, uncovered, at room temperature at least 30 minutes and up to 5 hours.

Step 8

Before serving, preheat oven to 500° and reheat roast until skin crisps (don’t let it take on any more color), 5–10 minutes.

Step 9

Remove chicharrón (crispy skin) and cut or break into smaller pieces. Slice pork and transfer to a platter. Serve with chicharrón and arroz y gandules alongside.