Preheat the oven to 220℃/Gas Mark 7.
In a small bowl or a pestle and mortar, mix or crush the fennel seeds, salt and pepper. If you haven't got a pestle and mortar simply mixing the ingredients in a bowl achieves the same results at the end of cooking.
Place the pork joint into the roasting tin. Using your hands spread the mixture of fennel seeds, salt and pepper all of the pork and in particular into the scored skin.
Pop in the oven and cook for 1½hours.
Whilst the crackling is roasting, peel and quarter the onions.
After 1½ hours remove the pork from the oven and tray. Pour away the fat from the tray and reduce the temperature of the oven to 130℃/Gas Mark ½.
Place the quartered onions, bay leaves and 750ml of cold water into the tray and sit the pork on top.
Return the pork to the oven and cook for approximately 3 to 4 hours until the meat is juicy and pulls apart.
Halfway through the cooking time (1½ - 2 hours), wash and score around the diameter of the apples and add them to the tray.
When the pork is ready and the apples are soft, remove them from the tray together some of the cooked onions whilst you prepare the gravy.
Mix 1-2 tbsp of cornflour with a little water to form a paste and stir this to the gravy in the tray on the hob on a medium heat. Once thickened using a sieve pour the gravy into a jug discarding the remaining onions and bay leaves.
To make the apple sauce, simply mash the softened apples with a fork removing any storks, cores and seeds.
Serve the pork with a piece or two of crackling, a spoonful of fresh apple sauce and a good helping of gravy.