Step 1

First score and prepare the pork skin, this is easiest when it is still fridge-cold. Score the skin all along the joint, then cut the skin and fat away from the top of the joint and along the contour of the joint, leaving around 5cm/2in intact at the base so it remains in one piece (this will create a flap where the stuffing will be added later). Leave out of the fridge to come up to room temperature.

Step 2

Preheat the oven to 220C/200C Fan/Gas 7.

Step 3

To make the stuffing, heat the oil in a frying pan. Gently fry the onion until soft and translucent, then remove from the heat to cool. Put the cranberries or prunes in a small saucepan with the calvados or brandy. Bring to the boil, then remove from the heat and leave until all the liquid has been absorbed. Combine the onions and cranberries or prunes with all the remaining ingredients, mixing thoroughly.

Step 4

Pull back the flap you have cut on the joint of pork and spread the stuffing over the exposed area. Replace the flap, then tie the joint together at intervals to help keep the stuffing in place. Rub the skin with oil and season with salt. Weigh the joint and work out the cooking time – it will take 30 minutes per 500g/1lb 2oz after the initial sizzle.

Step 5

Arrange the onions over the centre of a large roasting tin and top with the thyme sprigs. Place the pork on top. Put in the oven and roast for 20 minutes, then reduce the temperature to 180C/160C Fan/Gas Cook for the time you have worked out, sprinkling the cut sides of the apples with the sugar and adding for the last 45 minutes.

Step 6

Remove the pork, apples and onions from the roasting tin. Loosely cover with kitchen foil to rest. Drain off any liquid, then set the tin over a heat and stir in the flour. Stir to deglaze the tin and make a roux, then gradually add the cider and stir to a thick paste. Pour in the stock and any skimmed pan juices, then stir until the base of the tin is completely clean. Strain into a saucepan. Taste for seasoning and add a little apple jelly and calvados or brandy to taste (if using).