6 quarts water
1 1/2 cups kosher salt, plus more for seasoning
3/4 cup light brown sugar
1/4 cup coriander seeds
One 2-inch piece fresh ginger, sliced
2 bay leaves
1 gallon ice cubes
One 16- to 18-pound turkey, giblets removed
2 celery stalks, cut into 4 pieces
1 lemon, quartered
1 onion, quartered
4 sprigs parsley
1/2 cup pomegranate molasses
1 tablespoon Aleppo pepper
1 tablespoon unsalted butter
2 teaspoons soy sauce
For the brine and turkey: In a large stock pot, bring water, 1 1/2 cups kosher salt, sugar, coriander, ginger and bay leaves to a boil over high heat. Lower heat and simmer for 10 minutes, stirring occasionally to make sure the salt and sugar dissolve. While the brine is simmering, place the ice in a bucket or pot big enough to hold the turkey. Pour the brine over the ice. When the brine has cooled, add the turkey. Place a heavy object like a plate or lid on top of the turkey to keep it submerged in the brine. Refrigerate for 8 to 12 hours.
Position an oven rack on the lowest level of the oven and preheat the oven to 450 degrees F. Remove the turkey from the brine and pat it dry; discard the brine. Tuck the wings underneath the turkey. Sprinkle the turkey inside and out with salt. Put the celery, lemon, onion and parsley into the cavity of the turkey and tie the legs together with kitchen twine. Place breast-side down in a roasting pan fitted with a rack. Roast for 30 minutes.
For the glaze: While the turkey roasts, combine the pomegranate molasses, 3 tablespoons water and Aleppo pepper in a medium saucepan and bring to a simmer. Adjust heat and simmer, uncovered, until thick and syrupy, 5 to 10 minutes. Stir in the butter and soy sauce and remove from heat.
After 30 minutes of roasting, turn the turkey breast-side up and lower the oven temperature to 325 degrees F. Roast 3 hours longer, or until a meat thermometer inserted into the thickest part of the thigh but not touching bone registers 160 degrees F. When the thermometer registers 155 degrees F, or during the last 30 minutes of cooking, begin basting with glaze every 5 to 10 minutes. Remove the turkey from the oven and allow to rest for 15 minutes before carving.