Remove turkey from brine and drain all liquid. Pat dry.
Preheat oven to 425° Fahrenheit.
Put quartered onion, orange and herb sprigs inside the bird cavity.
Add the onion and apple wedges, prunes and about 2 cups of stock or broth to the bottom of a large roasting pan.
Rub the turkey all over and under the skin of the breast with the seasoned butter. Place the turkey on a rack in the pan.
Roast the turkey for 20 minutes, then reduce the oven temperature to 325°.
Baste the turkey every 20 minutes or so, adding additional stock, broth or water to the pan to keep about an inch of liquid. Halfway through roasting, pour ½ cup Aquavit over the bird. Tent loosely with foil once the skin is nicely browned.
Roast the turkey until an instant read thermometer inserted in the thigh reaches 170°. Remove from oven, transfer turkey to a cutting board and rest for at least 30 minutes before carving. Meanwhile, make the gravy.