Spray crock pot with non-stick cooking spray.
Place turkey and diced onions inside.
In a small bowl, mix together the water and onion soup mix; spread evenly over turkey.
In another small bowl, mix together remaining ingredients and sprinkle over the turkey breast.
Cook on low for 8 - 9 hours or the turkey reaches 165°F in the thickest part of the breast meat.
Remove turkey from crock pot and allow to rest 15 - 20 minutes prior to slicing and serving.