Blend until combined but still retaining some texture - it needs to be sticky enough to be able to easily mould into balls. However, be careful not to over-blend, as the mixture will become very greasy as the oils will be released from the nuts
Use your hands to roll the mixture into little balls - you should be able to make 14
Keeps in an airtight container in the fridge for a good few days
For a nut-free version, use sunflower seeds instead of walnuts, and use tahini instead of almond butter.