How to Make It
In a very large pot, combine the water, salt, brown sugar, paprika, juniper berries, peppercorns, star anise, cinnamon sticks, bay leaves and thyme and cook over high heat until the sugar and salt are dissolved. Remove from the heat. Squeeze the oranges into the brine and add the peels. Add the ice and stir until cool. Add the turkey. Refrigerate for 12 to 24 hours.
Preheat the oven to 325°. Drain the turkey and bring it to room temperature. Pat dry. Set the turkey on a rack in a large roasting pan and rub with the butter. Add 3 cups of water to the pan. Roast the turkey for about 3 hours, until an instant-read thermometer inserted in the thigh registers 170°. Transfer the turkey to a carving board; let rest for 30 minutes.
In a large saucepan, melt the butter. Add the diced giblets; cook over moderately high heat until lightly browned. Add the shallots and garlic and cook, stirring, until softened. Stir in the flour and cook for 1 minute. Add the sherry and whisk until thickened. Whisk in the stock. Add the thyme sprigs and bay leaf; bring to a boil. Simmer over low heat until reduced to 5 cups, 30 minutes. Discard the thyme sprigs and bay leaf. Stir in the chopped thyme.
Pour the pan drippings into a bowl; skim off the fat. Add the drippings to the gravy; simmer for 3 minutes. Season with salt and pepper. Carve the turkey and serve with the gravy.