Preheat oven to 200°C. Line two large baking trays with oven proof baking paper. Mix butter and sugar together in a bowl until smooth and creamy.
Add egg to butter mixture and mix again until smooth.
Stir flours and chocolate into the butter mixture. If the mixture seems a little dry, gently bring it together with clean hands. The warmth from your hands will be just enough to combine the mixture.
Roll tablespoons of mixture into balls, flatten slightly. Place balls onto lined trays. Bake for 15 minutes until slightly browned. Cool on wire racks.