Preheat oven to 180C/350F/Gas Mark 4. Line a baking tray with greaseproof paper.
In a large bowl, mash the bananas.
Sift in the tiger nut powder to remove any lumps and add all the other ingredients to the bowl. Mix until well combined.
Use a tablespoon to scoop the biscuit mixture onto the baking tray. Press down gently with the back of the spoon to flatten.
Bake for 15-20 minutes, until starting to turn golden brown on the bottom.
Remove from the oven and transfer the biscuits to a wire rack to cool.
Store in an airtight container for 2-3 days.