Mash all the butter ingredients together in a bowl with a little salt and plenty of pepper, tip into a lidded container and cover until needed. Will keep for up to three days chilled, or frozen for a month.

Up to 48 hrs and at least 12 hrs before cooking, loosen the skin of the turkey, over the breast, by pushing your hand beneath it. Season the turkey all over, including under the skin, with 1-2 tbsp flaky sea salt. (The further ahead you do this, the more succulent it will be.) Chop the turkey neck. Put the turkey in a large roasting tin or on an oven tray, breast-side up, and chill, uncovered, until ready to cook.

On the day of roasting, remove the turkey from the fridge at least 1 hr before cooking. Heat the oven to 200C/180C fan/gas 6. Remove the turkey from the tin and tip the onions, carrots, turkey neck and giblets into the tin. If you have one, sit a roasting rack, trivet or ovenproof cooling rack in or over the tray and sit the turkey on top. Put the lemon halves in the cavity of the turkey with the garlic and rosemary. Spoon the flavoured butter under the turkey skin, spread it all over the breast meat and as far down to the legs as possible. For a neat finish, tie the wings and legs together using butcher’s string. Drizzle half the oil over the turkey and rub it all over.

Put the turkey in the oven, roast for 1 hr, then remove, drizzle with the remaining oil, then return to the oven, turning the tin around, for another 1 hr. When the turkey has had 1 hr 45 mins in total, check it using a temperature probe thermometer – the timings differ depending on how long you’ve salted your turkey for and what breed of turkey you’re roasting. (If you don’t have a probe, see our tips, below.) Perfection is when the thickest part of the breast is about 65C and the thickest part of the thigh is 75C. If the temperature is lower, return the turkey to the oven for 15-min intervals and check again. Leave the turkey to cool for 10 mins on the rack, then use tongs to remove the lemon and garlic from the cavity and transfer to a board that has a moat or a platter to collect the resting juices. Leave to rest for at least another 20 mins (it will remain hot for at least 40 mins).

Meanwhile, make the gravy. If the roasting tin you cooked the turkey in is flameproof, put it straight on a medium heat, if not tip the contents into a large, shallow pan and put on the heat with the cooked lemon halves, garlic and rosemary sprigs. Scatter over the flour, stir to make a paste, then stir in the wine and soy sauce and sizzle for about 5 mins until it’s a thick paste. Stir in the stock and all the turkey resting juices and simmer for 5 mins, stirring all the time. Strain the gravy into a jug or another pan to reheat when needed. Carve the turkey and serve with your choice of sides, or carve at the table.