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 about 4-8 hours, up to 12.

Drain brine and let turkey breast dry until very dry or pat dry with paper towels.

Mix 3 tablespoons ghee, garlic, and thyme in food processor. Keep the elastic wrap on your turkey breast. Carefully, using your fingers, peel the skin away from the chicken breast and rub the butter mixture under the skin. You can also stick a spoon with ghee on it under the skin, then use your fingers outside the skin to hold the ghee down for you to remove the spoon. Rub the outside of the skin with 1 tablespoon ghee and season with salt and pepper.

Turn Instant Pot on Sauté mode. When hot, add 1 tablespoon ghee and sauté onions and garlic, stirring constantly, until slightly softened. Add cauliflower and chicken broth and stir. Place turkey breast on top of onion-cauliflower mixture, and put lid on Instant Pot, making sure valve is in Sealing position.

Cook on Manual High Pressure mode for 28 minutes. Then let naturally release for 10-15 minutes.

Remove turkey breast carefully and cut elastic wrap off. If desired, preheat broiler and broil turkey for a few minutes to brown skin.

Make the gravy: use an immersion blender, or transfer remaining mixture in Instant Pot cooking pot to regular blend, and process until completely smooth. Return to Instant Pot pot and cook on Sauté mode on Normal heat.

In a small bowl, combine 4 tablespoons arrowroot powder and 1-2 tablespoons water. Whisk until completely smooth, then add this arrowroot slurry to gravy in Instant Pot. Whisk vigorously to incorporate and let simmer until thickened to desired texture. Add coconut aminos for color and saltiness, but be careful: it's naturally sweet, so don't use too much. Add salt and freshly cracked pepper to taste.

Slice turkey breast and serve with gravy and my Whole30 Instant Pot mashed potatoes.