Directions

1. Up to two days before, salt the turkey. If you have a spice grinder or minichopper, tip in all the ingredients for the salt mix and grind to make a wet salt. If you are using a pestle and mortar, grind the herbs and pepper together, then add the salt and orange zest, and grind well again. Set aside. Carefully rinse the turkey and pat dry with kitchen paper. Sit the turkey in its roasting tin and use the salt mix to season the turkey generously all over. Put the turkey breast-side up in the tin, cover with cling film and leave in the fridge for up to 2 days. (This can be done a day ahead but the longer you leave it, the more the flavour of the salt rub will permeate the bird.)
2. To make the clementine & bay butter, mash all the ingredients together in a bowl with some seasoning and set aside. Can be made 2 days ahead or frozen for up to a month.
3. Remove the turkey from the fridge 1 hr before you want to cook it and rinse off all the salt really well. Pat it dry, rinse out the roasting tin, then sit the turkey back in the tin and leave at room temperature for about 1 hr, uncovered.
4. Heat oven to 180C/160C fan/gas 4. Calculate a cooking time of 40 mins per kg for the first 4kg of the turkey, then 45 mins for every kg after that. Rub the turkey all over with most of the butter - no need to season. If you haven't used the neck for the Make-ahead gravy (see 'goes well with'), then add the neck to the tin with the onion. Cover the tin loosely with foil and roast for the calculated cooking time. For the final 30 mins, remove the foil, baste the turkey, scatter with the reserved thyme and orange zest, and increase the oven temp to 200C/180C fan/gas 6. (Now is the time to pop in the stuffings and roast potatoes, if you are doing them.) When the turkey is beautifully brown and cooked through, remove from the oven and leave to rest on a warm platter covered loosely with foil and a tea towel.
5. If you've made our Make-ahead gravy (see 'goes well with'), you can add the roasting juices to that. To make your gravy fresh, pour off most of the fat but leave the juices in the tin and put it on a low heat. Stir in the flour to a paste. Pour in the sherry and sizzle for 1 min, then gradually add 850ml water and simmer until you have a thick gravy - make sure to scrape up the sides of the tin to release any bits. Sieve the gravy into a saucepan and reheat to serve - the gravy probably won't need extra seasoning as the turkey juices will be salty enough.