250g butter, softened but not melted
1½ cups cornflour
½ cup rice flour
¾ cup Chelsea Icing Sugar
1 tsp lemon rind, grated

Preheat oven to 150°C (130°C fan forced).
Mix all ingredients in a food processor until smooth and well combined.
Roll dough on a cornflour dusted surface to a 1cm thickness. Cut into fingers or press out shapes using cookie cutters.
Place on a baking tray lined with baking paper and prick with a fork. Bake for 25-30 minutes until pale but crisp (longer, slower baking is the trick with shortbread).
Cool on a wire rack and store in an airtight container.