Dry- fry the spices for the rub, then crush them using a pestle and mortar into a coarse powder.
Pat-dry the pork, score the top skin of the fat layer with a sharp knife, then rub all over the powdered spices. Put the pork on a tray and let it marinate for at least 2 hours, overnight if possible.
Preheat the oven to 160C. Take the pork out of the fridge at least 60 minutes before cooking. Wipe off the excess spice powder.
Cut the carrot and celery into large chunks. Core and cut the apple in half. Cut the garlic bulb in half. Cut the onion into wedges (shallots can stay whole).
Arrange the vegetables and apple pieces in a large roasting tray. Scatter the bay leaves and the sage on top. Season with salt and pepper.
Put the pork on top of the vegetables and roast for about 80 minutes, until golden. If you have a meat thermometer, check - the centre should be around 70C.
Transfer the pork, onions, garlic and carrots to a plate - cover with foil then a tea towel to keep warm.
Put the apples into a bowl. Remove the skin and mash the meat (you can add a drop of Calvados and a pinch of cinnamon to it). Discard the celery, bay leaves and sage.
Put the tray on the stove and make some gravy from the roasting juices – add a Tbsp of cornflour, apple juice or cider, chicken stock or vegetable stock and reduce, stirring constantly, until you get a thick sauce. Strain it into a jug.
If you want crackling, remove the rind with a sharp knife, put it on a tray and grill for 5-10 minutes until crispy.
Carve the pork and serve with the gravy, roasted vegetables and roasted apple sauce (see tip).