Roast a stuffed turkey breast weighing between 3 and 5.5 lbs. for up to 2 hours and 45 minutes in an oven preheated to 325 degrees Fahrenheit. Roast a stuffed turkey breast that weighs between 5.5 and 9 lbs. for up to 3 hours and 15 minutes. An unstuffed breast needs less time to cook thoroughly.
An unstuffed turkey breast weighing between 3 and 5.5 lbs. needs 90 minutes to 2 hours and 15 minutes to cook completely, while an unstuffed breast weighing between 5.5 and 9 lbs. needs 2 hours and 15 minutes to 2 hours and 45 minutes for proper cooking.
The breast requires extra time to bake if baked from a frozen state. Give a 3- to 5.5-lb. turkey breast between 3 hours and 3 hours and 45 minutes to cook. A 5.5- to 9-lb. turkey breast needs 3 hours and 45 minutes to 4.5 hours to cook.
Regardless of size, stuffed turkey breasts need to be baked until the thickest part of the breast reaches an internal temperature of 165 F, or 170 F for unstuffed breasts. A meat thermometer should be used to monitor the progress of the breast and avoid overcooking while ensuring the meat is baked until it is safe to eat. The breast should rest for 15 minutes after cooking for optimal flavor.