Preheat the oven to 220°C/200°C fan oven/gas 7.
Place the pork, skin side up in a roasting tray. Rub a little olive oil over the skin, and then rub in the fennel seeds and salt, making sure they go between the score lines. Place in the oven for 30 minutes then reduce the temperature to 160°C/140°C fan oven/gas 4 for 1 ½ - 2 hours, checking a couple of times throughout that the juices aren’t burning on the base of the tray. If they are, just add a cup of water into the tray. The longer you leave the pork to cook the crispier the skin will become.
By now the meat should be meltingly soft and the skin wonderfully crisp. You can continue to roast the pork if you want the skin even crispier.
Transfer the pork to a board to rest, covered loosely with foil.
To make the salad, heat the olive oil in a large frying or sauté pan and gently fry the fennel and green beans for around 8 minutes until just tender. Add the apple and chilli and cook for about 2 minutes until just becoming tender. Stir in the cannellini beans and stock. Bring to a simmer and cook for a couple of minutes until the beans are heated through. Season with salt and pepper and add a squeeze of lemon juice.
Cut the pork into six pieces (using a serrated knife is best to cut through the crispy skin) and serve with the warm bean, fennel and apple Salad.
To ensure really crisp crackling, the fat needs to be scored every 1cm or so with the tip of a very sharp knife. If you’re worried about scoring the fat yourself, ask your butcher to do it for you.
The skin can be rubbed generously with salt and left skin side down on a wire rack in a roasting tray in the fridge overnight to draw out excess moisture. Wipe/pat dry and prepare as above.