If you have time the day before, salt the turkey. Make the salt mix by grinding the salt with the thyme leaves and pepper in a spice grinder or with a pestle and mortar. Sit the turkey in a roasting tin and season all over, inside and out, using about two-thirds of the salt. Leave the turkey in the tin, breast-side up, cover with cling film and put in the fridge for up to 24 hrs. If you don’t have time, or there is no room in the fridge, simply prepare the salt and season the turkey generously before roasting.