Rinse the turkey breast and pat dry. If necessary, remove any excess skin, but leave the skin covering the breast. Rub softened butter all over and under the skin. Rub the onion soup mix all over outside of the turkey and under the skin.

Spray inside of the slow cooker with vegetable spray. Place carrots and celery into the bottom in a slow cooker. Pour in chicken broth. Place the turkey into the slow cooker, on top of the vegetables. Cover, and cook on High for 1 hour, then set to Low, and cook for an additional 7-8 hours. Use a meat thermometer to make sure it is cooked to an internal temperature of 165°F.

Remove to a platter and tent loosely with aluminum foil. Rest for at least 15 minutes before carving.

Enjoy!

Recipe yields about 12 servings.