Start 5 to 5 1/2 hours before you want to serve the cooked turkey. Set the oven temperature at Gas 3,160 C 325ºF. It is much better that the turkey be done 30 minutes before mealtime than to rush and serve an undercooked turkey. Remove the wrapping from the turkey and put the turkey on a rack on a pan that has been covered with foil to make cleaning easy . You can also cook the turkey in a covered roasting pan if you have one.
Put the turkey in the oven . Do not worry about the bag with the heart, liver, etc. in the neck cavity or the neck in the center of the turkey. They can be removed during cooking, after the turkey thaws. There will be Salmonella spp. and Campylobacter jejuni on the turkey. However, because it is frozen, there is no drip, and transfer to hands or counter is not a significant risk.
Cooking the turkey on a shallow pan on a rack assures even cooking. Cooking in a pan with sides shields the bottom of the turkey from heat, and the cooking on the bottom will be non-uniform.
In the first 2 to 2 1/2 hours, the legs and thighs get up to approximately 38C,100ºF. The breast, about 1 inch into the flesh, is still at the soft ice point, about -2C,25ºF. At this point, begin to monitor breast temperature with a tip-sensitive digital thermometer as it thaws. You may also use a dial roast thermometer. Insert it into the breast, because it is the slowest cooking part.
After about 3 1/2 hours, the legs and thighs will be around 60 to70C,150 to 160ºF, and the breast, about 5 to10C,40 to 50ºF. The bag of heart, liver, etc. and the neck can be removed at this time, to be made into stock, if desired (Fig. 3)

At 4 1/2 to 5 hours, the turkey is nicely cooked. Check the temperature. The leg and thigh should be tender and at a temperature of 80 to85C, 175 to 185ºF, while the breast will be moist at a temperature of 70 to 75C, 160 to 170ºF..