Anticipate and plan: If using a frozen turkey, begin thawing your turkey two to three days in advance in the refrigerator. This ensures a fully thawed bird ready for brining and roasting.
Craft your brine: In a generously sized stockpot, combine vegetable stock, salt, brown sugar, peppercorns, allspice berries, and candied ginger. Warm this mixture over medium-high heat, stirring occasionally until the solids have fully dissolved. Once the mixture reaches a boil, remove the pot from the heat, allow it to cool to room temperature, then refrigerate.
Brine the bird: The evening before you plan to serve the turkey, or early on the day of serving, combine the cooled brine, water, and ice in a 5-gallon bucket. Gently lower the fully-thawed turkey, with the innards removed, breast-side-down, into the brine. If necessary, use a weight to ensure the bird is completely submerged. Cover and refrigerate or set in a cool area for 8 to 16 hours, turning the turkey once halfway through the brining time.
Preparation for roasting: Preheat the oven to 500 °F and carefully remove the turkey from the brine and rinse it thoroughly under cold water, both inside and out. Dispose of the brine. Set the turkey on a roasting rack inside a half-sheet pan and pat dry with paper towels.
Aromatic touch: Combine apple, onion, cinnamon stick, and 1 cup of water in a microwave-safe dish. Microwave on high for 5 minutes. Then, add these steeped aromatics to the turkey's cavity along with sprigs of rosemary and sage. Tuck the wings of the turkey under its body and brush the skin generously with canola oil.
Elevate your bird seasoning: Generously dust the turkey with poultry seasoning, ensuring it's evenly distributed. This will imbue it with a rich, harmonious blend of flavors that will enhance its natural taste.
Roasting: Place the turkey on the lowest shelf of the oven and roast at 500 °F for 30 minutes.
Carefully insert a probe thermometer into the thickest part of the breast, and reduce the oven temperature to 350 °F. Set the alarm on your thermometer to 165 °F. A 16-pound turkey should typically require between 2 and 2.5 hours of roasting time. (The brine speeds up the cooking process.)
Rest and carve: Allow the roasted turkey to rest, loosely covered with foil or a large mixing bowl, for 15 minutes before carving. This resting period allows for the juices to redistribute, resulting in a moist, flavorful bird. Now, it's time to serve and enjoy!