Process all ingredients, except caster sugar, together in a food processor until mixture resembles fine breadcrumbs

Press mixture together until it forms a dough. Divide dough in two

Roll out dough between 2 sheets of baking paper until 5mm thick

Using a snowflake-shaped cutter, cut shapes from dough. Transfer to prepared trays. Sprinkle with caster sugar if desired. Bake at 160°C for 30 minutes or until dry and firm but still pale. Transfer to a wire rack to cool completely. Dust with icing sugar. Serve