Heat a little oil in a deep casserole dish with a lid. Put the pork, skin side facing down, and cook until it’s crispy. Brown the meat all over, then transfer it to a plate.
Meanwhile,thinly slice the garlic, onion and celery. Peel and cut the parsnips and carrots into large chunks.
Preheat the oven to 160°C.
Remove the excess fat from the pan, then sauté the onion and celery for 5 minutes. Add the garlic and fennel seeds, then stir for a couple of minutes. Add the Sherry and apple juice then reduce the liquid by half.
Put the meat back, then scatter some oregano all over it. Pour the chicken stock around the pork. Bring to the boil, cover and put the dish in the middle of the oven for 1.5 hours. Baste the meat a couple of times with the jus.
Remove the dish from the oven, and put the carrot and parsnip chunks around the pork. Add more chicken stock if you think it’s getting dry.
Roast for another hour, then serve.