For herb butter: (You can make the herb butter ahead of time, then soften on the counter while your turkey is also on the counter.)
Soften butter by leaving out at room temperature 30-60 minutes, or in a microwave for 5-10 seconds.
Chop herbs and mince garlic, if using. Mix with butter in a small bowl.
For turkey:
Be sure to thaw the turkey ahead of time if frozen! This can be done 1-2 days before. We thaw it partially in the refrigerator and partially on the counter (don’t leave it out so long that it is no longer cold to touch). It can take up to 3 days to thaw exclusively in the refrigerator.
About one hour before cooking, set the thawed turkey on the counter to get rid of the chill. Remove package of giblets that is usually inside the turkey cavity. Store these in the refrigerator until ready to make giblet gravy. Place turkey on a baking sheet lined with foil or in a roasting pan. (A disposal aluminum pan is fine if you don’t own one.)
Loosen the skin of the turkey, starting at the neck, by running a finger under the skin. Work as far down the breast as possible, without tearing the skin. Go to the cavity end of the turkey and loosen skin from that side. Now get about a tablespoon of the butter at a time and push under the skin with your fingers; cover the breast meat and into the area where the legs join the body.
Place any leftover herbs sprigs into the cavity. If desired, cut the peeled onion and lemon into quarters and stuff into the cavity as well.
Truss the turkey legs, if desired. To truss: cut a 16-inch piece of cooking twine. Wrap it around the tail and tie. Cross the drumsticks and bring one end up and around where the legs cross. Then bring other end up and around the opposite side and direction. Bring both ends to top side and tie in a knot. Bend the wings backward and tuck the tips under the back. (See How to Truss a Chicken or Turkey for pictures.)
Brush oil over the turkey then sprinkle salt and pepper generously over it.
Remove all racks in the oven except one. Place it in the bottom third of the oven. Preheat oven to 450°F. Continue to leave turkey on counter while you wait for the oven to heat. Time things so the turkey is out of the refrigerator for about 30-60 minutes.
When hot, place turkey in the oven and cook on high heat for 30 minutes. After 30 minutes, turn heat down to 350°F, baste, and set timer for 1-1/2 more hours for an 8-10 pound turkey. Add about 13-15 minutes for each additional pound. Baste the turkey every 30-45 minutes. Remember, this timing is for a turkey that is NOT stuffed.
When the turkey has about 30 minutes left to cook, use a meat thermometer if you have one (we highly recommend) and stick it in the thickest part of the thigh, making sure it’s not touching a bone. The turkey is done when the internal temperature is about 165°F. Chef’s Tip: If you don’t have a meat thermometer, or if it seems inaccurate, cut a slit in the thickest part of the thigh when you think the turkey is done. The juices that run out should be clear with no tinge of pink.
Remove the turkey from the oven when done and let rest about 20 minutes before cutting to give it time to reabsorb the juices.