Salt the turkey: Mix the salt, dried rosemary, sage, thyme, peppercorns, bay leaves, and lemon peel in a small bowl. Rinse the turkey inside and out (do not pat dry). Pull any fat pads from the main and neck cavity of turkey; wrap, chill, and reserve fat for roasting. Slip the bird into an turkey-sized oven roasting bag (other plastic bags, such as grocery or garbage bags, are not food-safe) to contain the juices, and refrigerate overnight. The juices mingle with the salt, and become heavier and force themselves throughout the bird via osmosis, essentially seasoning the bird from the inside out. Rinse and dry the bird before roasting.

Position the rack in the lower third of the oven and preheat to 325ºF. Rinse the turkey inside and out; pat very dry. Stir the chopped onion, celery, lemon, rosemary, sage, and thyme in small bowl. Divide the onion mixture between main and neck cavities. Fold neck skin under and secure with skewer. Tuck wing tips under. Tie the legs together loosely. Spread the butter all over turkey. Tightly cover the breast area (not the wings) with aluminum foill Place the turkey on a roasting rack set in large roasting pan. Place reserved fat pads and reserved neck, heart, and gizzard in pan; pour in 2 cups of turkey stock.

Roast the turkey for 45 minutes. Baste, including under the foil, with the pan juices. Continue to roast until thermometer inserted into thickest part of thigh registers 165 degrees F to 170ºF, basting every 45 minutes, adding stock or water to the pan if dry, 3 to 3 ½ hours longer. Remove the foil during the last hour of roasting. Transfer the turkey to a platter and let rest 30 tminutes. Reserve the roasting pan with juices for gravy.

Make the gravy: Remove turkey neck, heart, and gizzard from roasting pan. Pull meat off neck; chop neck meat heart and gizzard and reserve or gravy, if desired. Pour pan juices into 8-cup measuring cup . Spoon off fat from surface, reserving ½ cup fat. Add enough turkey stock to degreased pan juices to measure 5½ cups total, using water, if needed.

Place roasting pan over 2 burners on medium heat Add ½ cup reserved fat and shallots; sauté 1 minute. Whisk in flour. Cook until roux is light brown, whisking constantly, about 2 minutes. Whisk in wine, stock mixture, mustard, and fresh rosemary. Bring to boil, whisking to blend. Boil until gravy coats spoon, about 3 minutes. Add neck, heart, and gizzard if desired. Season with salt and pepper.

Carve the turkey and serve with the gravy.