Heat the oven to 230°C/450°F/gas mark 8, or as hot as your
oven will go. Place the pork (with its very dry skin – this is
really important as we want it to crackle) on a suitably sized roasting tin. Season all over with salt, then place in the hot oven for 25–30 minutes. Once the crackling is looking good, remove the pork and turn the oven down to 190°C/375°F/gas mark 5.
Scatter the red onion wedges over the base of a large, clean ovenproof dish. Carefully lift the pork from the hot roasting tin and set it down on top of the onions.
Wind a piece of bacon around the circumference of each apple, hold it in place with a tooth pick. Place the apples around the pork, scatter over the sage leaves, bay and fennel tops (if using) and season well with salt and pepper. Sprinkle over the crushed fennel seeds and trickle everything with the olive oil.
Place the pork and bacon wrapped apples in the oven and cook for a further 35 minutes, until the pork is cooked through and the apples are soft but not collapsing. (It’s worth noting that if the apples look like they are going to collapse, you can take them out of the oven and allow the pork to finish cooking without them.)
Remove the pork dish from the oven and allow the meat to rest in
a nice, warm place for 10–15 minutes. Serve everyone a few thick slices of pork, some generous strips of crackling, an apple and some herby juices.