In a large stockpot, combine the sea salt, brown sugar, and cold water. Stir until the salt and sugar are completely dissolved.
Submerge the turkey in the brine solution. Cover and refrigerate for 12 hours or overnight.
Preheat the oven to 350 degrees F (175 degrees C).
Remove the turkey from the brine, rinse it thoroughly under cold water, and pat it dry with paper towels. Discard the brine mixture.
Brush the turkey inside and out with half of the melted butter.
Season the cavity of the turkey with freshly ground black pepper.
Stuff the cavity with 1 chopped onion, 2 chopped carrots, 2 chopped celery stalks, 1 sprig of rosemary, the lemon quarters, and the halved garlic head.
Place the turkey breast-side down on a roasting rack in a shallow roasting pan.
Scatter the remaining onion, carrots, celery, and rosemary in the bottom of the roasting pan. Add the bay leaf.
Pour the white wine over the vegetables in the pan.
Roast the turkey in the preheated oven, uncovered, for about 3 ½ to 4 hours.
About two-thirds of the way through the roasting time, carefully turn the turkey breast-side up and brush with the remaining melted butter.
The turkey is done when the juices run clear and an instant-read thermometer inserted into the thickest part of the thigh, near the bone, reads 165 degrees F (74 degrees C).
Once cooked, remove the turkey from the oven and let it rest for 30 minutes before carving. This allows the juices to redistribute throughout the meat, ensuring a moist and flavorful turkey.
Carve the turkey and serve it on a platter, accompanied by the roasted vegetables from the pan.
