Line a 20cm brownie tin with baking paper and heat oven to 160°C
Add drained chickpeas, tahini, melted butter or oil, maple syrup and vanilla extract to a blender and blitz until very smooth
Slowly pour in the milk whilst blitzing until well combined and smooth, adding in 2-3 batches if needed
Combine flour, baking powder, 75g white chocolate, salt and hazelnuts in a large bowl
Melt 100g white chocolate in a microwave at 20 second bursts, stirring between bursts until melted
Pour the chickpea mixture and melted chocolate into the dry ingredients and stir and fold gently
Pour the mixture into the lined tray
Drizzle over the maple tahini mixture made by whisking 50g tahini and 50g maple syrup with a little water
Scatter sesame seeds over the top
Bake for 28-30 minutes until the blondies are set at the edges and lightly golden but still soft in the centre
Allow to cool and firm up, then slice into squares
