• Preheat oven to 400 degrees. Lay the celery and onions in a single layer in the center of a large roasting pan.
• Remove the giblets and neck from turkey. Discard giblets (or use for another recipe) and place the neck in a small saucepan and set aside. Pat the turkey dry with a paper towel (so the butter sticks) and bend the wing tips under the body. Set the turkey, breast side up, on the vegetables in the prepared pan.
• Mix salt, pepper, and thyme together in a small bowl. Brush the turkey all over with the melted butter and sprinkle with the salt mixture.
• Roast, uncovered, for 40 minutes, until lightly browned.
• Make Stock: Meanwhile, add vegetable scraps to the saucepan with the turkey neck, cover with water and bring to a boil. Reduce heat to low, and cook, covered, while turkey roasts to make broth.
• Remove turkey from oven and reduce temperature to 350 degrees. Pour the cup of white wine over the turkey and cover the pan tightly with foil, tenting the center to avoid touching the turkey breast as much as possible.
• Roast 1 hour. Remove foil, baste with pan juices and roast for another 30-60 minutes (uncovered) or until an instant-read thermometer reaches 165 degrees when inserted into the thickest part of the thigh.
• Remove turkey from pan to a platter or cutting board and cover with foil to rest for 20 minutes before carving.

Make Gravy:

• While the turkey is resting, strain the pan drippings into a 4-cup glass measure. Add neck broth as needed to equal 2½ cups.
• Pour 1/2 cup of the liquid into a medium-sized saucepan and heat on medium-high. Slowly whisk in the 1/4 flour until smooth. Add remaining 2 cups of liquid slowly and cook over medium heat, whisking constantly until thickened, about 3-5 minutes. Taste to adjust seasonings and serve immediately with turkey.