Turkey Gravy:
6 quarts water 4 tablespoons all-purpose flour
1 1/2 cups kosher salt 1 cup cream Sherry or apple cider
1 tablespoon cracked black pepper 2 cups chicken broth
4 bay leaves 1/4 cup heavy cream
14 to 16-pound turkey, neck and giblets reserved
8 ounces unsalted butter, softened
Juice and zest of 3 oranges
1 tablespoon fresh thyme, chopped
1 tablespoon fresh sage, chopped + 4 fresh sage sprigs
salt & pepper, to taste
2 cups chicken broth

Line an extra-large stock pot with a large-heavy plastic bag (a 30 gallon trash bag works great!).
Combine the water, salt, pepper and bay leaves and stir until dissolved.
Rinse the turkey and reserve the neck and giblets.
Place the turkey in the brine and refrigerate for 10 to 18 hours.

Preheat the oven to 350°F.
Drain the turkey well and discard the brine.
Pat the turkey dry and place it on a rack in a large roasting pan.
Tuck the wings underneath the turkey and tie the legs together loosely.
Season the bird liberally with salt and pepper.
Place the reserved turkey neck and giblets in the bottom of the roasting pan.
Stir together the butter, orange juice, orange zest, thyme and sage until well blended.
Carefully lift the turkey skin from the breast meat and rub 1/4 cup of the butter mixture under the skin.
Rub the remaining butter over the outside of the bird.
Stuff the orange rinds and sage sprigs inside the cavity of the turkey.
Pour 2 cups of chicken broth into the roasting pan.

Roast the turkey for the first hour without opening the oven.
Then continue roasting the bird for approximately 2 1/2 to 3 hours more, basting with the pan drippings every 30 minutes.
Cover the bird loosely with foil if it is browning too quickly.
Roast the turkey until a meat thermometer inserted in the thickest part of the thigh registers 180°F.
Transfer the turkey to a serving platter.
Tent the turkey with foil and let is stand for 20 minutes before carving.

Remove the turkey neck and giblets from the pan and discard.
Skim the fat from the pan juices, reserving 1/4 cup of the fat, and place the roasting pan on top of the stove over high heat.
Add the sherry or cider to the pan juices and scrape up any brown bits from the bottom of the pan.
Bring the mixture to a boil, then remove the pan from the heat.

Place the reserved fat in a large saucepan over medium heat.
Add the flour and whisk to create a roux, whisking constantly for 3 minutes, or until golden in color (a roux is a cooked mixture of flour and fat used to thicken the gravy).
Add the sherry mixture, broth and cream and whisk to combine.
Simmer the gravy until thickened to desired consistency, about 5 minutes.
Season to taste with salt and pepper.