Blend the frozen berries, banana, yogurt, half the milk and the acai berry powder in a liquidiser or blender until smooth. Try it, and if it’s not sweet enough, add the dates and blend again. It should be thicker than a regular smoothie but runny enough to pour.Add more almond milk a bit at a time to get a pourable smoothie, and divide between small bowls. Top with as many toppings as you like, and serve straight away.