Using a large, very sharp knife, cut and peel skin away from the meat in one large piece; reserve skin. Remove and discard as much fat as possible from the layer. In a small bowl combine 1/2 cup salt, the sugar, 2 tablespoons thyme and the garlic. Place pork belly on a rack set in a shallow pan. Rub salt mixture evenly on all sides of the belly. Chill, covered, overnight.Advertisement
Line a large roasting pan with foil. Place a rack on top of the foil; set pan aside. Rinse pork belly and skin and pat dry with paper towels.
In a very large skillet, cook fennel, onion, parsley, 2 tablespoons thyme, the rosemary and 1 1/2 teaspoons salt in hot oil over medium heat for 10 to 15 minutes or until onions and fennel are tender, stirring occasionally. Remove from heat; let cool completely.
Score the meat of the pork belly in a diamond pattern with shallow diagonal cuts, spaced 1-inch apart. If using, replace skin back on pork. Turn pork belly skin side down. Using paper towels, dry completely. Sprinkle meat side of pork belly with fennel pollen and pepper. Spread fennel mixture evenly over the pork belly, leaving a 2-inch border on each side. Starting with the longer side, roll belly around filling; tie in several places with 100%-cotton kitchen string. If you’ve used the skin, pierce the roast all over the top, sides and bottom with a knife. (You can’t pierce it too much. This helps the fat escape and tenderizes the skin.) Cut roll in half cross-wise. Place both halves on rack in prepared pan.
Roast in a 310° oven about 2 hours or until an instant-read thermometer inserted into the center of the pork reaches 135°F. Increase oven temperature to 450°F. Roast for 40 to 50 minutes more, turning roasts a quarter turn every 10 to 12 minutes to crisp sides and bottom of roasts evenly. Remove from oven; let stand for 25 minutes before slicing.
* Pork belly skin:
Crispy skin is one of the pleasures of porchetta, but if you’re squeamish about it (or can’t be bothered with the prep), just order a skinless belly. You’ll still be taking advantage of pork belly’s richness and intense porky flavor.