For the turkey: Twenty-four hours before cooking your turkey, liberally season the inside and outside of the bird with salt and pepper. Using a mini chopper or mortar and pestle, grind the oregano, parsley, tarragon, sumac, thyme, shallots and lemon zest together with some salt and pepper; the salt will help draw the moisture and flavor from the mixture. Add the olive oil to form a paste. Spread the herb mixture all around the inside and outside of the turkey. Refrigerate the turkey, uncovered to dry the skin, for 24 hours.
For the roasting: Remove the turkey from the fridge 90 minutes before roasting and allow it to come to room temperature.
Preheat the oven to 450 degrees F.
Season the turkey again with salt and pepper. Put the parsley and thyme sprigs in the cavity with the lemon and shallot halves.
Put the carrots, celery and onions in the bottom of a roasting pan fitted with a roasting rack. Add a cup of water or stock to the bottom of the pan. Add the turkey to the rack and roast, adding a little more water or stock to the pan if necessary to prevent the drippings from burning, for 30 minutes. Reduce the temperature to 350 degrees F and continue to roast, basting the turkey with the pan drippings every 30 minutes, until the thickest part of the leg registers an internal temperature of 155 degrees F, another 2 1/2 to 3 hours. Allow the bird to rest, tented with foil, for at least 1 hour before carving. The temperature will rise to about 165 degrees F during resting.
Pour the pan drippings into a saucepan, set the pan over medium-high heat and cook until reduced by one-half, about 10 minutes. Stir in the butter until melted. Pour the reduced turkey drippings over the carved turkey just before serving.