Make the brine: Stir together all ingredients until salt is totally dissolved. Pour brine into large food storage container or Ziploc bag and place turkey breast in brine. Seal completely and refrigerate 12 hours.

Drain brine and let turkey breast dry until very dry. Pat dry with paper towels if necessary.

Preheat oven to 350º F.

Mix 3 tablespoons ghee, garlic, and thyme in food processor. Carefully, using your fingers, peel the skin away from the chicken breast and rub the butter mixture under the skin. If necessary, depending on your turkey breast, tie breast with kitchen twine to keep the breast tight. Rub the outside of the skin with the remaining 2 tablespoons ghee and season with salt and pepper.

In a roasting pan, fitted with a rack, place turkey, breast side up. Roast 1 hour then baste with any drippings. Roast another 15-20 minutes or until internal temperature reads 160º F. Remove from oven, loosely tent turkey with foil, and let rest while you make the gravy.

Heat drippings or ghee over medium heat, in your roasting pan or in a saucepan if desired. Add onions and cook, stirring frequently, until onions are softened and start to brown. Stir in garlic and cook, stirring frequently, until fragrant, about 30 seconds. Stir in cauliflower, thyme sprigs, and turkey stock and bring to a simmer. Simmer until cauliflower is fork-tender, about 10 minutes. Remove thyme stems.

Transfer mixture to blender and blend until smooth.