Method

​1 Line a couple of baking trays with baking parchment paper.

2 Put the butter and sugar into a large bowl and cream together, using an electric hand-held whisk or wooden spoon, until light and fluffy. Add the gluten-free plain flour, cornflour and salt into the bowl. Mix together until smoothly combined. Lightly knead the dough inside the bowl.

3 Roll out the dough between 2 pieces of cling film to a thickness of 1cm. Prick the dough all over with a fork and cut into triangles or whatever shapes you like, using a knife or a biscuit cutter. Re-roll the scraps once to cut more.

4 Put the shortbread on the prepared baking trays and chill in the fridge for 30 minutes. Meanwhile, heat your oven to 170°C/fan 150°C/gas mark 3.

5 Bake the shortbread for 20 minutes, or until just turning golden brown at the edges. Leave on the baking trays for a few minutes to firm up slightly, then lift the shortbread onto a wire rack. Dust with caster sugar and leave to cool. They will keep in an airtight container for 3-4 days.