Method

• 1.
  To make the stuffing, blanch cavolo nero in a saucepan of boiling water and refresh in iced water. Drain well and chop. Place sourdough, cavolo nero, herbs, spices, tomatoes and olive oil in a food processor and whiz until well combined. Place in a large bowl with the sausage mince and season. Using your hands, mix until combined. Chill until required.
• 2.
  Lay pork belly out, skin-side down, and butterfly the meat from the centre outwards on one side to separate meat from the skin without cutting all the way through, then open out to 1 large piece. Season meat and spread evenly with stuffing. Roll into a log so the skin is over the top and not rolled into the centre of the porchetta. Cut 8 pieces of butcher’s twine long enough to tie around the pork and lay them at even intervals on a bench. Place the rolled pork onto the twine and tie a knot in each to firmly secure the pork. Season skin with salt and leave uncovered in the fridge overnight or for up to 24 hours

• 3.
  Preheat a fan-forced oven to 250°C. Place a wire rack inside a roasting tray and place porchetta on the rack with the seam underneath, drizzle with olive oil and season all over with fine cooking salt. Roast for 30 minutes. Reduce heat to 180°C and roast for a further 1 hour 25 minutes or until skin is crackling and meat is cooked. Remove from oven and rest porchetta for 15 minutes before carving.