For the turkey: Remove the turkey from the refrigerator 1 hour before roasting.
Combine the butter, parsley, rosemary, sage and thyme and in a food processor and process until smooth. Season with salt and pepper.
Preheat the oven to 450 degrees F. Sprinkle the cavity of the turkey with salt and pepper and fill the cavity with half the carrots, celery and onions. Rub the entire turkey with the herb butter and sprinkle liberally with salt and pepper.
Put 4 cups of the chicken stock in a medium saucepan and keep warm over low heat.
Place the remaining vegetables on the bottom of a large roasting pan. Put the turkey on top of the vegetables, put in the oven and roast until lightly golden brown, about 45 minutes. Reduce the heat to 350 degrees F and continue roasting, basting with the warm chicken stock every 15 minutes, 2 to 2 hours 15 minutes hours longer. (An instant-read thermometer inserted in the thigh should register 160 degrees F.)
Remove the turkey from the oven, transfer to baking sheet, tent loosely with foil and let rest 30 minutes before slicing. Remove the legs for braising. Strain the drippings into a bowl and discard the solids. Add enough stock to make 4 cups liquid.
Bring the liquid to a simmer, transfer to a roasting pan, add the legs, cover with foil and braise until tender in a 350 F degree oven about 1 hour.
For the gravy: Melt the butter in a medium pan over high heat. Add the roasted garlic and cook for a minute. Whisk in the flour and cook until lightly golden brown. Slowly whisk the drippings into the flour mixture, bring to a boil and whisk until the mixture begins to thicken and the flour taste has been cooked out, about 5 minutes. Add a splash of the white wine if desired and cook for 1 minute longer. Fold in fresh herbs if desired and season with salt and pepper. Serve immediately.