For the spiced pork, mix all of the spiced pork ingredients (except for the pork) together in a bowl until well combined.
Put the pork shoulder into a shallow ovenproof dish and rub all over with half of the dry spice rub mixture. Cover loosely with cling film and chill in the fridge for 1-2 hours. (Reserve the remaining dry spice rub mixture).
Once the pork has marinated for two hours, massage the remaining spice rub mixture into it. Preheat the oven to 150C/300F/Gas 2.
Transfer the spiced pork to a large roasting tin, pour 100ml/3½fl oz water into the tin, then cover with a large piece of aluminium foil, pinching the foil around the edges of the tin to seal well. Cook the spiced pork in the oven for five hours, or until tender.
Meanwhile, for the barbecue sauce, heat the oil in a frying pan over a low heat. Add the onion and fry until softened but not coloured, about 10 minutes, then add the garlic and fry for a further 2-3 minutes.
Add the remaining barbecue sauce ingredients and gradually bring the mixture to a simmer, stirring well. Continue to simmer for 10-15 minutes, or until the mixture has thickened and the onions are very soft. If desired, set the barbecue sauce aside to cool slightly, then blend to a smooth purée in a food processor. Set aside, covered, to cool, then chill in the fridge until needed.
For the baked apples, fill the hole in the middle of each apple with the sugar and butter.
Place each stuffed apple into a roasting tray and cover with aluminium foil, then set aside until the pork has cooked for four hours. Add the baked apples to the oven and bake for 40 minutes, then remove the foil covering and bake for a further 10-15 minutes, or until the apples are very soft but not collapsing.
For the potato salad, half-fill a saucepan with water and bring to the boil. Add the potatoes and a pinch of salt and return the water to the boil. Cook for 15-18 minutes, or until just tender. Drain in a colander and then suspend under running cold water until completely cooled.
Mix together the mayonnaise, crème fraiche, capers, gherkins, lemon juice and parsley in a large bowl until well combined.
Cut each of the potatoes into quarters and stir them into the mayonnaise dressing. Season, to taste, with salt and freshly ground black pepper.
When the pork is cooked, transfer to a chopping board, cover with a sheet of aluminium foil and a clean dry tea towel and set aside to rest for 15-20 minutes.
Meanwhile, for the sage and onion stuffing, increase the oven temperature to 180C/350F/Gas 5.
Heat the oil in a frying pan over a medium heat. Add the onion and garlic and fry for 4-5 minutes, or until softened but not coloured.
Mix together the breadcrumbs, parsley and sage in a bowl until well combined. Add the cooked onion and garlic mixture and the egg yolk and stir well to combine. Season, to taste, with salt and freshly ground black pepper.
Spoon the sage and onion stuffing mixture into a small ovenproof dish and bake in the oven for 25-30 minutes, or until cooked through.
When the spiced pork has rested, shred it using two forks.
To serve, fill each bread roll with the spiced pulled pork and top the pork with a spoonful of barbecue sauce. Serve the baked apples and potato salad alongside.