INSTRUCTIONS
1. Combine water, salt, parsley, coriander, peppercorns, mustard seeds, garlic powder, and bay leaves in a large stockpot and bring to a boil. Boil until salt has dissolved, about 2 minutes. Let cool for 15 minutes. Stir in buttermilk.
2. Rinse turkey in cold water. Place in a brining bag and pour buttermilk brine over the top. Refrigerate for 24 hours, turning occasionally.
3. Discard the brine and rinse turkey thoroughly in cold water. Pat turkey dry with paper towels and place breast side-up in a roasting pan. Rub butter over all of the skin and let turkey sit for 1 hour.
4. Preheat the oven to 350 °F.
5. Cook turkey until an instant-read thermometer inserted into the thickest part of the thigh, near the bone, reads 165 °F , about 3 hours.
