Add other ingredients and blend at low speed for 10 seconds. This version has 192 calories and 3 grams of protein per cup. Blend all at low speed about 10 seconds. Using the partially frozen liquid will produce a much colder, thicker shake. Omit butterscotch sauce.
Place partially frozen liquid in blender, then add peanut butter mixture.
Blend for about 10 seconds or until smooth. Pour shake into small container. Freeze 2 hours or until it begins to harden around edges. Scrape into bowl and mix thoroughly, until lumps disappear. Return to container and refreeze 2 hours or until firm.