Preheat the oven to 240C/fan220C/gas 9, or as high as it will go. Unroll the pork and score the skin for the crackling. Sprinkle the meat side with sage and lemon zest, then season.
Reshape the joint and tie with string at 2cm intervals. Weigh to calculate the cooking time and salt the skin. Put in a lightly greased roasting tin, skin side up.
Roast for 20 minutes. Reduce the oven to 180C/fan160C/gas 4 and roast for the calculated time. Meanwhile, for the stuffing, fry the onion gently in the butter until soft and lightly browned. Tip into a bow and stir in the breadcrumbs, zest, sage and parsley.
Season to taste. Stir in the egg, then spoon into a lightly buttered, shallow ovenproof dish and rough up the surface with a fork. Cover and set aside. Half an hour before the pork is ready, peel, core and quarter the apples. Melt the butter in a medium-sized pan, add the apples, season and toss gently, then spoon around the pork and return the tin to the oven.
Brush the top of the stuffing with a little melted butter and roast alongside the pork. When the pork is cooked, remove from the oven and rest, uncovered, for 10 minutes. Lift the apples into a dish, cover and keep warm. Turn the oven off.
Lay a sheet of foil on the stuffing and leave in the oven to keep warm. To make gravy, pour the excess fat from the tin and put it over a medium heat on the hob. Stir in the flour and gradually stir in the stock, scraping up all the juices from the base as you go. Bring to the boil, then simmer until reduced. Strain into a gravy boat. Remove the string from the pork, slide a knife under the crackling and lift it off.
Carve the meat and serve with the crackling, stuffing, gravy and apples.View more Pork recipes...