Prepare the Brine: Add two cups of the buttermilk, hot sauce, garlic, bay leaves, smoked paprika, black pepper, onion powder, and rubbed sage to a small saucepan over medium heat and bring to a light boil. Reduce heat to low and simmer for 20 minutes, then remove from heat and cool to room temperature. Dissolve the salt in this mixture.
3 quarts buttermilk, ½ cup coarse salt, ¼ cup hot sauce, 8 cloves garlic, 4 bay leaves, 2 tablespoons smoked paprika, 1 ½ tablespoon black pepper, 1 ½ tablespoon onion powder, 1 tablespoon rubbed sage
Spatchcock the Turkey (optional, but encouraged): Lay a thick dishcloth out on the counter, then place your cutting board on top of it to prevent slipping and sliding. Place the turkey, breast-side down on the cutting board, then use kitchen shears to cut along both sides of the backbone, about one inch at a time, alternating sides between cuts so that you make equal progress all the way down. Remove the backbone.
10-14 pounds uncooked bone-in turkey
Remove the turkey neck and giblets and set aside for the gravy.
Flip the turkey over so that it is breast-side up, then spread out the legs, and firmly press down on the breastbone to spatchcock the turkey. You will know it’s done properly when you no longer hear the cartilage make a popping sound and the bird is able to lie completely flat.
Brine the Turkey: Add turkey to a brining bag, then pour in the infused buttermilk and cold buttermilk. Squeeze out any air as you seal the bag then place in the refrigerator to brine for 24 to 48 hours (the longer the better), turning the turkey every 12 hours so that it evenly marinates.
Cook the Turkey: Remove the turkey from brining bag, letting the excess buttermilk drip into the bag then place it on a sheet pan and allow it to come to room temperature (about 45 minutes to one hour).
Preheat oven to 450 degrees Fahrenheit. Place turkey on a sheet pan lined with a wire rack, aluminum foil, or parchment paper, wrap the wing tips with aluminum foil, then transfer to the oven to roast for 30 minutes. Reduce the heat to 400 degrees Fahrenheit and continue cooking for 40 minutes or until the internal temperature reaches 160 degrees Fahrenheit. If parts of the turkey are browning too much or too quickly, tent them with aluminum foil.
Make the Gravy: While the turkey roasts, add turkey neck, giblets, and backbone if using to a saucepan with broth over medium-high heat. Bring to a boil, then reduce heat to low, cover and simmer for an hour. Remove from heat, strain the liquid into a heat-safe bowl, and discard the turkey parts.
reserved turkey neck, giblets, and/or backbone, 4 cups broth
Add butter to saucepan over medium heat and allow to melt, then add onion until fragrant (four minutes). Whisk in the flour until it's dissolved in the butter and mixture turns a golden brown (about three minutes). Whisk in the reserved buttermilk and strained turkey stock until smooth. Continue cooking for 15 minutes or until thickened and bubbly, then remove from heat. Taste test and add seasonings, as needed.
4 tablespoons unsalted butter, ½ onion, ¼ cup all-purpose flour, ¼ cup reserved buttermilk from the brine
Finish and Serve: Allow turkey to rest for about 30 minutes so that the juices can redistribute and residual heat can bring it to 165 degrees Fahrenheit. Carve or serve whole with gravy, and aromatic garnishes like orange slices, fresh sage, rosemary, etc.