Turkey breasts are known for providing a lean, flavorful source of protein that can be easily prepared in the oven. The average turkey breast weighs from 4 to 8 lbs., but sometimes you need a large turkey breast weighing 9 lbs. to accommodate a large dinner. While preparing a 9-lb. turkey breast follows the same basic procedure, cooking time is adjusted slightly so the internal temperature of the meat reaches the minimum safe amount.
Preheat the oven to 325 degrees Fahrenheit.
Rinse the turkey breast and pat dry with paper towels.
Place the turkey breast skin side up on a roasting rack inside a roasting pan.
Use a basting brush to apply a thin layer of vegetable oil to the top of the turkey breast.
Place the turkey breast into the oven and cook for about 3 to 4 hours.
Check the internal temperature of the turkey breast after 3 hours by inserting a meat thermometer into the thickest part of the meat.
Remove the turkey breast when the internal temperature reaches 165 degrees.
Allow the turkey breast to cool for 20 minutes before serving.