Let the turkey sit on the counter for 45 minutes before roasting.
Roast the bird in a 325-degree oven. You can roast it breast-side down on a piece of buttered parchment, turning the bird right side up after 1 hour. Or roast it breast-side up, covering it with oiled cheesecloth or a loose foil tent after 1 hour. A bird is cooked when a meat thermometer inserted into the thickest part of the thigh and the stuffing registers 160 degrees. Let the turkey rest in a warm place for at least 20 minutes. The temperature will rise 10 degrees.
A cooked turkey is fine on the counter for 1 hour. After that, remove the stuffing, if necessary, and transfer it to a buttered dish. Reheat the stuffing. Do not reheat the turkey.
These times are approximate.
UNSTUFFED
8 to 12 pounds 1¾ to 2 hours
12 to 14 pounds 2 to 3 hours
14 to 18 pounds 3 to 4 hours
18 to 22 pounds 4 to 4½ hours
STUFFED
8 to 12 pounds 2 to 2½ hours
12 to 14 pounds 2½ to 3¾ hours
14 to 18 pounds 3¾ to 4½ hours
18 to 22 pounds 4½ to 5 hours
Source: The Boston Globe, November 20, 2012