Step 1

Melt the butter in a medium saucepan over medium heat. Add the onion and garlic and sauté, stirring often, for 15 to 20 minutes, until the onion becomes browned and starts to caramelize. Sprinkle on the flour, and cook, stirring constantly, for 1½ minutes. Stir in the chicken stock, brandy, sage leaves, bay leaves, 2 teaspoons salt, and 1 teaspoon pepper, depending on the saltiness of the chicken stock. Bring to a boil, lower the heat, and simmer for 15 minutes, stirring occasionally. Set aside at room temperature for 1 hour and strain, pressing the solids lightly, and then discarding them. Refrigerate until ready to use.

Step 2

After the turkey is cooked, remove it to a carving board to rest while you finish the gravy. Place the roasting pan on the stovetop over a medium heat and add the white wine. Bring to a boil, lower the heat, and simmer for 2 minutes, stirring and scraping up all the bits clinging to the bottom of the pan. Slowly whisk the gravy base into the pan. Simmer for about 5 minutes, until the gravy is smooth and slightly thickened. Taste for seasonings and serve hot.

Step 3

To make ahead, make the gravy base and refrigerate for up to a week. Finish with the turkey pan juices from the turkey plus the wine, season to taste, and serve hot.