Thaw turkey breast, if frozen. Remove the giblets from the cavity. Rinse the turkey breast and pat dry with paper towels. Loosen the skin on top of the breast with your fingers.

Combine butter, herbs, spices and salt in a small bowl. Spread half of the mixture under the skin and spread the remaining mixture on top of the skin.

Place the trivet in the Instant Pot and pour in the chicken broth.

If the turkey breast has a cavity place the onion and celery there. If it is open, just lay them in the Instant Pot pan and place the turkey breast in the vessel, breast side up.

Close and lock the lid on the Instant Pot. Set valve to “sealing”, choose “Pressure Cook” / "Manual" and choose 32 minutes on HIGH Pressure. It will take roughly 15 minutes to come to pressure, with 32 minutes of cook time. When the time is up, allow the pressure to release naturally for 20 minutes. Switch to “venting” and carefully open the lid.

Preheat the broiler. Remove the turkey gently with two large metal spatulas or spoons. Place the turkey breast skin side up on a baking sheet. Broil 3 to 5 inches from the broiler for 3 to 5 minutes or just until skin in golden brown.

While the turkey broils, strain 2 cups of turkey drippings from the Instant Pot into a sauce pan and bring to a simmer. Sprinkle the xanthan gum over the simmering drippings and whisk to thicken.

Pour gravy over turkey and serve.