1 cup boiling water
1 package low fat cream cheese (3 oz)
1 small box of sugar-free Jello (any flavor)
1 cup diet soda (any flavor)

Combine first 3 ingredients in blender and blend until thoroughly dissolved. Add soda and blend once more to ensure a smoother consistency.

Chill overnight. Top each serving with sugar-free cool whip.

(I used cherry jello and kiwi strawberry soda and blended with an immersion blender)