Directions

1. Heat oven to 180C/160C fan/gas 4. Line a roasting tin with a very generous length of double-thickness foil. Weigh the turkey to calculate the cooking time, allowing 40 mins per kg for the first 4kg, then 50 mins for every kg over that weight (a turkey this size should take 3 1/2 -4 hrs).
2. Put the butter in a bowl and finely grate the zest from the orange on top. Add the chopped tarragon, garlic and seasoning and mix well. You can make this 3 days ahead.
3. Gently push your fingers under the turkey skin, starting from the neck end of the bird, easing the skin away from the breast and the top of the drumsticks. Now spread the flavoured butter under the skin, taking care not to tear it. You won't be able to reach all the way down to the drumsticks, but you can ease the butter along by smoothing it through the skin. Quarter the orange and tuck into the turkey cavity with the onion and the bunch of tarragon (step-by-step). You can do this the night before.
4. Season the turkey with salt and pepper, then lift it onto the foil-lined roasting tin. Pour the wine into the cavity of the turkey, then bring up the sides of the foil and cover the top of the bird with a layer of foil. Roast according to your calculated time.
5. Thirty mins before the end of cooking time, remove the foil from the top of the turkey and add the potatoes to the oven.
6. To test if the turkey is cooked, pierce the fattest part of the thigh with a skewer - the juices that run out should be clear, not pink. If they are pink, continue to roast, checking at 10-min intervals.
7. Remove the turkey, transfer to a warm serving platter and let it rest, covered loosely with the foil, for 30-40 mins before carving. Meanwhile, turn up the oven to 200C/180C fan/gas 6 and cook the potatoes for 30 mins more, with the stuffing and sausages. Serve the turkey decorated with herbs.