Perfectly cooked turkey

Remove the turkey from the fridge at least an hour before cooking and heat the oven to 220C/fan 200C/gas 7. Calculate the cooking time – allow 30 minutes at high heat, then 30 minutes per kilo after you have reduced the heat. So a 5kg turkey will take three hours in total.

Put the sliced onions into the roasting tin. Put the turkey on a rack and then put the rack into the roasting tin. Drizzle the turkey with olive oil, and season well. (If you’ve brined the turkey, skip the seasoning as it will be well seasoned already.)

Pour 2 cups of boiling water into the tin with the onions and cover the whole thing with a double layer of foil. Make sure that it’s well sealed around the edges. Put the tray in the oven and cook for 30 minutes, then reduce the temperature to 200C/fan 180C/gas 6 for the remaining cooking time.

After 11⁄2 hours remove the foil and close the door. Don’t open it again until the cooking time is up. To test whether the turkey is cooked, insert a skewer or knife blade into the point where the thigh joins the breast — the juice should run clear. If it is pink, leave it for another 20 minutes and test again. Alternatively insert a digital thermometer into the thickest point – it is cooked when it reads 72C.

Take the bird from the oven, remove the onions, then strain the juice in the bottom of the tin into a large jug to settle. The fat will rise to the top, leaving the turkey and onion juice beneath. Skim off the fat and use the juice to make a gravy if you wish or serve as it is. Leave the turkey to rest in a warm place covered with foil for 1 hour, then carve.