What do you need:

10-15 blueberries + 20 blueberries from the freezer

5 strawberries

10 drops greensweet liquid stevia blue berry

This is how you make it:

Puree the 15 extra berries together with the strawberries to a fine mass.

Add everything in the jar and pour with two / three liters of water while stirring.

The frozen berries work like ice cubes and keep the drinks cool for hours !!!!!

Source: Monique van der Vloed