Question: how long do you cook a fully cooked frozen turkey?
Answer: Calculate your roasting time. Thawed turkeys require about 15 minutes of cook time for every pound of meat. With a frozen turkey, you need at least 50 percent longer, or about 22 ½ minutes per pound. A 12-pound turkey, which would cook in about three hours if it's fully thawed, now requires 4 ½ hours.