1 Place the almonds in a bowl and cover with the water. Leave to soak overnight until the almonds are soft.
2 The next day, drain the almonds, reserving the soaking water, and give them a quick rinse.
3 Combine the soaking liquid, almonds, and vanilla extract in a food processor or blender.
4 Blend until milky and smooth. Pour the milk into a bowl lined with a double layer of cheesecloth. Strain the milk, twisting the cheesecloth to extract as much milk as possible.
5 Pour the milk back into the food processor or blender and add the frozen berries and agave nectar.
6 Blend until smooth and divide between glasses before serving.