1. Preheat the oven to 220°C, gas mark 7. Pat the skin of the pork joint dry with kitchen paper then season and rub well into the scored skin. Arrange the sliced vegetables over a large roasting tin, add the wine or cider and place the joint on top. Roast for 30 minutes then reduce the heat to 160°C gas mark 3 and cook for about 4–4½ hours, until the pork is very tender, there is no pink meat and the juices run clear. Cover loosely with foil for the last hour.
2. Meanwhile, place the vinegar in a medium pan with 200ml cold water, the sugar and spices. Warm over a low heat until the sugar slowly dissolves then bring to the boil. Add the pear quarters and simmer for 30 minutes until tender.
3. Using a slotted spoon transfer the pears to a clean, warm, sterilised jar so that they just fill it. Return the pan of liquid to the heat and boil for 5-6 minutes until reduced by half. Pour over the pears to cover them completely, screw on the lid and leave to cool (see cook’s tip).
4. Remove the crackling and carve the pork into thick slices. Serve with crackling and any pan juices spooned over and with the pickled pears alongside.