Question: how to cook a fully cooked frozen turkey?
Answer: Heat the oven to 325°F. ... 
Place the turkey in the roasting pan: Unwrap the turkey and place it on top of a roasting rack inside a roasting pan. ... 
Roast for 2 1/2 hours. ... 
Check the temperature: This temperature check is just to get a reference point for how quickly the turkey is cooking.