Porchetta with pickled celeriac and sorrel

For the marinade, mix all the ingredients together to make a wet rub. Spread it evenly on the flesh side of the pork belly, trying to keep the skin dry. Leave to marinate in the fridge, uncovered and skin side up, overnight. To make the pickled celeriac, peel the celeriac, keeping the skin for the sauce. Cut the celeriac in half and cut it into slices 1–2 mm (1/16 inch) thick – use a mandoline, if you have one. Put the wine, vinegar, sugar, spices and thyme into a small, non-aluminum pan with 150 ml (5 fl oz) of water and simmer for 5 minutes, then pour it over the sliced celeriac and cover. Let it pickle in the liquid until completely cold, then refrigerate until needed – it will keep well for a few days.

When you’re ready to cook the porchetta, preheat the oven to 100°C (200°F) fan-forced. Trim the pork loin so it will t lengthwise inside the belly. Arrange over the flesh side of the pork belly and roll up as tightly as possible, using string to tie it securely every 1.5–2 cm (¾ inch) along its length. Put the porchetta on a wire rack in a roasting tin and pour a 1 cm (½ inch) depth of water into the tin. Cook in the oven for 2½–3½ hours, or until the meat’s core temperature is 64°C (147°F); start checking with a probe thermometer after 2 hours.

While the porchetta is roasting, make the sauce. In a large frying pan over medium-high heat, saute the onion and the reserved celeriac skin in the vegetable oil until they’re well browned, almost burnt. Transfer to a saucepan and cover with the chicken stock or water, garlic, thyme and bay leaf. Bring to the boil, then simmer for 1–2 hours until the liquid has reduced to 200–300 ml (7–10½ fl oz). Strain the reduction through a fine sieve into a clean pan and bring back to a simmer. Stir in the butter and 2–3 tablespoons of the liquid from the pickled celeriac, season with salt and simmer for 1–2 minutes until emulsified.

Once the thermometer registers the right core temperature, remove the porchetta and turn the oven up to 250°C (480°F). When the oven has reached temperature, return the meat and cook for 10 minutes, then rotate the tin and cook for another 10 minutes or until the skin is pued up and really crispy. Let the porchetta rest for about 10–15 minutes before removing the twine. To serve, cut the porchetta into slices about 2–3 cm (1 inch) thick and place a slice on each plate. Spoon some sauce around it, then top with 5–6 slices of the pickled celeriac, a few sorrel leaves and a generous drizzle of olive oil.