Using paper towels, pat the turkey dry. Season the turkey on the interior and exterior with kosher salt, concentrating on the breast and thighs. Cover the turkey with plastic wrap, breast-side up, in the roasting pan. Refrigerate the turkey for at least 2 days before serving.
Turn the turkey breast-side down, wrap it in plastic wrap, and keep it refrigerated for another day.
The night before, you want to roast the turkey. Remove the plastic wrap and arrange it on a rack over a baking sheet. Cool the turkey for at least 8 hours to allow it to air dry.
Allow 1 to 2 hours for the turkey to come to room temperature before patting dry with paper towels. Season the turkey with black pepper and stuff the cavity with onion and celery.
Preheat the oven to 425 degrees Fahrenheit (220 degrees C). In a roasting pan, place the turkey breast-side down.
Roast for 30 minutes in a preheated oven until the skin is brown. Please take out the turkey oven and turn it breast-side up. Bring the oven temperature to 325°F (165°C); continue roasting for another 2 hours until thigh registers 165°F (74°C).
Place the turkey on a large dish and cover loosely with aluminum foil; set aside 30 minutes before carving.