melted butter, to grease
250g butter, at room temperature
100g (1/2 cup) caster sugar
300g (2 cups) plain flour, sifted
90g (1/2 cup) rice flour, sifted
1. Preheat oven to 150°C. Brush 2 baking trays with melted butter to grease. Use an electric beater to beat the butter and sugar in a bowl until pale and creamy.
2. Gradually add the combined flour, beating on low speed until almost combined. Use your hands to bring the dough together in the bowl. Turn onto a lightly floured surface and knead gently until smooth.
3. Divide the dough into 2 equal portions. Use your hands to shape 1 portion of dough into an 18cm-diameter disc. Transfer to 1 of the prepared trays. Use a flat-bladed knife to smooth the surface. Pinch the edges to create a fluted edge. Use a small sharp knife to score the disc into 8 wedges and use a fork to prick the dough all over. Repeat with the remaining dough to make a second disc.
4. Bake the shortbread in oven, swapping the trays halfway through cooking, for 40 minutes or until light golden. Set aside on the trays for 10 minutes to cool before transferring to a wire rack to cool completely. Cut into wedges to serve.