Cream butter and icing sugar. Combine and sift potato starch, plain flour and milk powder into creamed butter in batches. Mix until a soft dough is formed. Divide dough into 3 parts and add any preferred food colouring to each. Knead again. Take small amount of the dough and roll into small balls. Use fork to make a straight dented pattern.

Bake at 150°C - 160°C for 15 minutes or until the base turn lightly brown. Leave to cool completely before storing.