Pre-heat oven to 180C degrees (160C degrees fan-forced). Line an oven tray with baking paper.
Place peanut butter, maple syrup, banana, egg and vanilla in a large mixing bowl. Mix with a fork or a whisk until well combined.
Add the oats, oat flour, arrowroot, baking powder and cinnamon, mixing well to combine. Fold in the choc chips, walnuts and chia.
Dollop tablespoons of mixture onto baking tray and bake for 12-15 minutes until just golden underneath. Remove to a wire rack to cool completely.