Mix the sugar, butter and egg in a planetary mixer. Transfer to a bowl and add the flours and Balsamic Vinegar. Knead the mixture with your hands until you obtain a smooth and consistent ball. Let it rest in the fridge for at least 30 minutes covered with cling film.

After the resting time has elapsed, make 2 cm diameter balls, place them on a baking sheet lined with baking paper, flatten them slightly and bake at 180°C for about 15 minutes or until the biscuits are golden brown. 

Once baked, allow them to cool completely on a wire rack before serving.