Remove any excess fat from inside the cavity of the duck, then using a sharp knife carefully score the breast and legs all over in crisscross fashion, roughly 1cm apart. Season the duck with salt, pepper and the five-spice, rubbing all over so the flavour catches in all the nooks and crannies. Halve the clementine and place it into the cavity along with the bay leaves. Place the duck in a medium-sized roasting tray, cook at 180°C/350°F/gas 4 for around 1 hour 20 minutes.
When the time’s up, remove the duck from the oven and drizzle your par-boiled veg (see Gorgeous roast vegetables) with some of the fat from the tray then toss to coat (save the remaining fat for another day). Lift up the duck, scatter the garlic, carrots and onions into the tray and sit the duck back on top. Cook for a further 40 minutes, or until the duck is beautifully crisp and the meat falls easily away from the bone.
Remove the duck to the tray of roast veg while you finish your gravy. Add the flour to the broken-down veg, then mash everything together with a potato masher, scraping up all the sticky goodness from the bottom. Place over a medium-high heat. Pour in the Marsala, stir well and let the alcohol cook off for a minute or two. Add the stock, then bring to the boil and reduce to a simmer for around 15 minutes, or until thickened and reduced. Strain through a coarse sieve, skim away any fat from the surface, then season to taste. Shred or carve up the duck, then serve with a jug of gravy, apple and cranberry sauce, crispy roast veg and all the trimmings.