- 1 4-pound pork belly (with or without rib bones)
- 4 teaspoons kosher salt plus more
- 2 teaspoons freshly ground black pepper plus more
- 6 poblano chiles, stemmed, coarsely chopped
- 3 habanero chiles, stemmed, sliced into 1/4″ rounds
- 3 serrano chiles, stemmed, chopped
- 1 cup agave syrup (nectar), divided
- Vegetable oil
- 1 ripe pineapple (about 3 1/2 pounds), peeled, cored, cut into 1/2″ rounds
- 1/4 cup apple cider vinegar
- Ingredient info: All chiles are available at better supermarkets, farmers' markets, and Latin markets. Agave syrup (nectar) is available at better supermarkets and natural foods stores.
- Preheat oven to 250°F. Season pork belly all over with 4 teaspoons salt and 2 teaspoons pepper.
- Place chiles in a large roasting pan. Place pork belly, skin side down, on top of chiles; drizzle with 1/2 cup agave. Pour remaining 1/2 cup agave and 2 cups water into pan. Cover pan tightly with lid or two layers of foil.
- Transfer to oven and cook pork for 3 hours, basting with pan juices every hour. Turn pork over. Cook until very tender, about 4 more hours.
- Transfer pork to another roasting pan (if bone-in, remove and discard bones). Strain liquid from first roasting pan into a saucepan (there should be about 5 1/2 cups); reserve chiles. Gently boil juices until reduced to about 1 1/4 cups, 45-50 minutes; add reserved chiles. Remove pan from heat. Let glaze cool; chill.
- Meanwhile, cover pork with parchment or waxed paper. Top with a large plate. Place weights, such as large canned goods, on top. Chill overnight.
- Reheat glaze. Build a medium-hot fire in a charcoal grill, or heat a gas grill to high. Brush grill rack with oil. Grill pineapple until nicely charred, 2-3 minutes per side; place on plates.
- Let grill cool to medium heat. Slice pork belly into 1″-thick pieces. Grill until warmed and crisp, about 3 minutes per side. Brush pork with some of the glaze from chile sauce.
- To serve, place 2 or 3 pineapple slices on each plate; spoon glaze over, then top with pork belly. Drizzle with vinegar.