Preheat the oven to 200oC. Grease and line a 20cm square baking tin with parchment.
Heat the milk and protein powder in a small saucepan to just below boiling, remove from the heat and add the dates, leave to soak for 5 minutes.
Place the dates and any liquid in a food processor and pulse to give a coarse paste. Crumble in the wheat biscuits and add the Walnuts, egg and cinnamon and pulse again to give a coarse texture. Stir in the seeds and press into the prepared tin, smooth out the surface and sprinkle with the remaining Walnuts, pressing them in slightly.
Bake for 20 minutes and allow to cool; brush with maple syrup, if using, then cut into 12 bars.
