Heat the oven to 200C/180C fan/gas 6. Bash the garlic, sage, lemon zest, salt and pepper together using a pestle and mortar until the mixture becomes a paste. Stir in the oil, then spread the mixture over the pork shoulder, avoiding the skin on top. Score the skin using a sharp knife, then rub a large pinch of salt into the skin. Tie the pork together using kitchen string.

Line a large baking tray with a double layer of foil and put the pork on top, skin-side up. Bring the sides of the foil up around the pork to create a parcel, then pour the wine into the tray around the sides. Transfer to the oven and reduce the temperature to 140C/120C fan/gas 1. Roast for 4-5 hrs, or until a meat thermometer inserted into the thickest part of the pork reads 70C.

Turn the oven up to 240C/220C fan/gas 9. Carefully spoon the pork roasting juices from the pan into a saucepan and cook over a medium heat for 10-15 mins, or until reduced by a third. Season to taste.

Meanwhile, arrange the foil around the meat so only the skin is exposed, then return to the oven for 10-15 mins until the skin is puffed up and browned all over. Leave to rest for 20 mins before slicing. Serve with the sauce drizzled over.