I found a frozen yogurt recipe! I will try this, but will substitute strawberry yogurt for a stronger strawberry flavor and see how it is.
https://www.vitamix.com/us/en_us/Rec..._st=&sc=recipe
I am concerned about using frozen fruit again, though. I am afraid my chest freezer keeps things frozen too hard for the Vitamix. If I burn out the motor I wonder if they will replace it?