1. Combine first 5 ingredients and 6 cups apple cider in a stockpot over medium-high heat; bring to a boil. Reduce heat, and simmer 10 minutes or until sugar and salt dissolve. Stir in remaining 6 cups apple cider. Cool mixture completely.
2. Rinse turkey with cold water. Place in a turkey-size oven bag, and place bagged turkey inside a second bag; add cider mixture to first bag with turkey. Secure bags. Refrigerate 12 to 24 hours, turning occasionally. (If space is lacking in your refrigerator, secure bags, place in a beverage cooler, and cover with ice. Check periodically and replace ice, if necessary.)
3. Remove turkey from bags, and discard brine. Rinse turkey with cold water; drain and pat dry with paper towels.
4. Loosen and lift skin from turkey with fingers, without totally detaching skin; spread 1 tablespoon Creole seasoning under skin. Sprinkle 1 tablespoon seasoning inside cavity. Sprinkle turkey skin with remaining 2 tablespoons Creole seasoning. Let turkey stand 30 minutes.
5. Preheat oven to 325°. Place turkey on a roasting rack, breast side up; brush entire bird with melted butter. Roast about 3 hours or until a meat thermometer inserted into thickest portion of thigh registers 180°. (Shield turkey with aluminum foil after 1 hour to prevent excessive browning, if necessary.) Brush with pan juices occasionally during last 60 minutes of cooking. Let stand 15 minutes before carving.