To make the spice mix, blitz all of the ingredients in a food processor to a fine powder. Pour through a coarse sieve into an airtight jar, then discard any woody bits left behind in the sieve. With a fork or the tip of a sharp knife, prick the fatty lump under the goose’s wing to help the fat melt out. Rub the goose all over with a little olive oil and 2 heaped tablespoons of the spice mix, making sure you get into all the nooks and crannies. Keep the remaining spice mix for another day – it’s incredible on all roasted or grilled meats. Prick the clementine all over with a sharp knife, then place into the goose's cavity with a few rosemary sprigs.
Peel and quarter the onions, then chop the carrots and celery into large chunks. Place into a large roasting tray with the remaining rosemary, the bay and goose giblets. Toss well, add 150ml of cold water, then place the tray on the bottom shelf of the oven. Pop the goose directly on the bars above, so the juices from the goose drip into the tray, leaving you with crisp, beautifully succulent meat. Cook for around 3 hours, or until cooked through, golden and crisp. To check, insert a skewer into the thickest part of the thigh – if the juices run clear, it’s done.
When the goose has been roasting for 2 hours, remove the veg tray from the oven and replace it with another tray. Skim away the fat from the veg tray (reserve it in a jar with a few extra bay leaves to make amazing roasties or my sweet glazed carrots), then place the tray on the hob over a high heat. Add the port and cook for around 3 minutes, or until reduced. Stir in the flour for a minute, then pour in the stock. Reduce to a simmer for around 10 minutes, or until thickened to a nice gravy consistency. Sieve into a medium pan, then set aside.
When the time’s up on the goose, remove it from the oven, cover with a double layer of tin foil and a tea towel and leave to rest for 20 to 25 minutes. Remove the tray from the oven, skim away and reserve the fat, then pour any juices into the gravy. Warm up the gravy on a medium heat.
Once rested, place the goose on a board and remove the skin – pop this into the oven for another 10 minutes to crisp it up nicely (keep an eye on it!). Carve away the legs, then shred the meat with two forks, discarding the bones. Carefully slice away the breasts, then slice up and place on a platter with the remaining shredded meat. Halve the pomegranate, then holding it in the palm of your hand cut-side down over the platter, bash the back with a wooden spoon so the seeds come tumbling out. Snap the crispy skin over the top, then serve with your hot gravy and all the trimmings.