1. Preheat the oven to 150C.
2. Place the joint in a roasting tin, and pat down well with kitchen roll until dry. Using a very sharp knife (a stanley knife or scalpel is good for this) score the skin in a criss cross pattern – this will help to render the fat and allow it to crisp up later.
3. Rub the pork all over with the sea salt and cumin, then transfer to a medium shelf in the oven to roast for 6 hours.
4. Meanwhile, core the apples, leaving a generously sized cavity, and stuff with the black pudding, and set aside.
5. Once the pork has had 5 hours, turn the oven temperature right up to 230C, and cook for a further 1 hour to crisp the crackling.
6. Pop the apples and sliced onions in alongside the pork for the last 45 minutes, stirring the onions well into the rendered cooking liquid. You may need to move the pork to a lower oven shelf if it looks like it’s getting too dark after 35-40 minutes.
7. Once cooked, remove the pork to a platter or board, and the apples to a serving dish, and cover the pork loosely in foil to rest for 15 minutes.
8. Place the roasting tin on the hob, and turn up the heat until the cooking liquid and onions start to bubble. Use a wooden spoon to scrape up the sediment, and then pour in the cider. Bubble for 5 -6minutes until reduced, then pour into a wide necked jug. The fat will settle to the top after 2-3 minutes, so ladle this off and reserve for future use, or discard. Season to taste with sea salt and freshly ground black pepper.
9. Serve the pork alongside the apples, gravy and mashed potato.
