Turkey is one of the easiest birds to cook and over-cook, simply because of its physiognomy, or at least how the turkey industry breeds turkeys to be. As most people know, the turkey breast finishes cooking long before the turkey legs and thighs are done, which need more cooking since they're all muscle and sinew.
Adding to the problem of roasting a turkey is that it's desirable to showcase a perfectly cooked bird for friends and family; consequently roasting a turkey's dark and white meats separately isn't generally preferred.
However you choose to season your turkey is up to you. There are usually numerous side dishes at Thanksgiving and Christmas, and in some regard, the turkey serves almost like a condiment to the side dishes. The turkey shouldn't be aggressively flavored with herbs and spices, especially if you've bought an organic turkey, the natural flavor of which will be more pronounced than a Butterball.
Choosing the Turkey
Name brands and market-chain brands stock supermarket meat cases, and if you can afford a few dollars more, you should consider purchasing an organic free-range turkey. The bird itself has lived a more humane life than the industry-bred turkey and will have eaten its natural diet of seeds, nuts, fruits and insects, which contribute to a more robust flavor and delicious meat.
Fresh or thawed, the turkey skin should be cream colored with a pink hue around the breast meat and a rosy, almost purple color around the drumsticks.
The turkey should have no noticeable odor.
Brining is a popular way of infusing the turkey with salt, liquid and herbs to increase flavor and prevent the turkey from drying out during roasting. The brining process works in adding juiciness, particularly to the turkey breast. However, a downside of brining is that it substantially changes the texture of the meat, giving it an almost spongy quality.
If you're roasting an organic turkey, I wouldn't recommend brining, since the brine will affect the turkey's natural flavor. However, if you're roasting a conventionally raised turkey, brining will have a positive effect on the meat.
Preparing the Turkey
A 15-pound frozen turkey will take at least 3 days to properly defrost in the refrigerator. A general rule of thumb is 24 hours per 4 to 5 pounds of turkey. Since you'll need the turkey completely defrosted the day before you're going to roast it, definitely plan ahead and calculate how many days your turkey will need in the refrigerator.
Another method is to defrost the turkey in cold water -- never hot water -- but it will require a lot more effort on your part to do it properly.
Once the turkey is fully defrosted, remove the giblets and refrigerate separately (the neck, heart and gizzard should be used for the gravy). Pat the turkey dry with paper towels. Measure out 2 tablespoons of Kosher salt and sprinkle the turkey all over, making sure to get underneath the turkey and in between the drumsticks and wings.
Set the turkey on a drying rack in a baking sheet, then refrigerate the turkey uncovered for 1 full day. The salt will be absorbed into the meat, which will allow it to retain moisture when roasting, and the air-drying in the refrigerator will yield crispy skin. (A similar process is used in preparing Peking duck.)
Take the turkey out of the refrigerator two hours before roasting. At this point, you can choose to stuff the turkey cavity or not (don't stuff the turkey until just before you're going to put it into the oven). I'm not a champion of stuffing a turkey, since an unstuffed turkey roasts quicker and more evenly.
Aromatic vegetables stuffed into the turkey cavity, however, don't affect its roasting time and add a lot of flavor to the pan drippings, which you'll use to baste the turkey and to make gravy.
Cut an onion in half and stuff it into the turkey cavity, along with 2 carrots and 2 celery ribs, cut into thirds, and several sprigs of Italian parsley.
There's really no need to worry about trussing the turkey, although a lot is made about this. Simply use butcher's string to tie the two drumsticks together, and tuck the wings underneath the neck.
Preheat the oven to 450°F. Arrange the turkey on a rack in a roasting pan. You can smear softened butter all over the turkey, massaging it into the skin, or alternatively, add 2 cups of turkey stock into the pan. Sprinkle the turkey with Kosher salt and several good grinds of freshly ground pepper, then put the turkey drumsticks-first into the oven.
Turn down the heat to 350°F and roast approximately 13 minutes per pound, basting every 20 or 25 minutes with the pan juices.
If the breast is browning too quickly, cover loosely with foil.
IMPORTANT: Check the internal temperature of the turkey with an instant-read thermometer after 1-1/2 hours to ensure the turkey isn't over-cooked. When the internal temperature at the thickest part of the thigh reaches 155°F, take the turkey out of the oven and let it rest at least 30 minutes before carving.
An alternative method is to take the turkey out when the breast meat hits 150°F and carving off the entire breast. While it rests, put the turkey back into the oven and let the dark meat finish cooking in about 20 minutes.