Preheat your oven to 220°C (430°F). Pat the pork belly dry with paper towels, then carefully score the skin in a deep crosshatch pattern without cutting into the meat. Rub the coarse sea salt generously into the skin, pushing it into the cuts, and let it sit at room temperature for about 30 minutes to help dry out the skin for crisping.
While the pork rests, prepare the apple puree. Peel, core, and chop the apples into chunks. Place them in a saucepan with a splash of water, a squeeze of lemon juice, and the teaspoon of sugar if using. Cook over medium heat, stirring occasionally, until the apples are soft and starting to break down, about 15 minutes.
Once the apples are soft, remove them from heat and blend until smooth using a blender or immersion blender. Stir in a little lemon juice for brightness, then set aside.
Place a wire rack on a baking sheet and set the pork belly on top. Drizzle the meat side with the neutral oil to keep it moist. Roast in the hot oven for 30 minutes to start rendering fat and bubbling the skin.
Lower the oven temperature to 180°C (350°F). Continue roasting the pork for 1 to 1.5 hours, basting occasionally with rendered fat. If you have herbs like thyme or a bay leaf, tuck them under the pork for aroma. Keep an eye on the skin; if it isn’t bubbling and crisping, increase the heat slightly or broil for the last 5 minutes, watching carefully.
Once the skin is deep golden and bubbling, remove the pork from the oven and let it rest uncovered for at least 10 minutes. This helps the juices settle and keeps the skin crisp.
While the pork rests, reheat the apple puree if needed. Slice the pork belly into portions, ensuring each piece has some crackling skin intact. Plate the slices and spoon the bright, smooth apple puree on the side.
Finish with a sprinkle of flaky sea salt or fresh herbs if desired, then serve immediately for the ultimate crispy, tender, and tangy contrast.
