Cream together the butter (200g) and caster sugar (100g).

Sift the plain flour (200g) and rice flour (100g) into the butter and sugar mixture and add in the vanilla extract (1 tsp). Mix together until combined - You don't want to work the mixture too hard, if you have an electric mixer then use a low to medium setting for about 1 minute. If you are using your hands then squeeze the mixture together before kneading lightly until you have a soft dough.

Roll out the dough to a depth of about 2cm and place onto baking parchment in a baking tray. I found that a rectangle shape of about 16cm long and 12.5 cm wide meant that I could cut the dough into 10 fingers, however make whatever shape you want! To roll the dough I found it easier to first lay out some clingfilm on the work surface, put the dough on top of that and roll it flat a little, and then put baking parchment on top of the dough. I then rolled out the mixture to the proper dimensions with the baking parchment still on top. This meant I could then easily flip the dough onto the baking tray with the baking parchment now at the bottom and cling film covering the top.

Put the baking tray in the fridge for at least 30 minutes to help the mixture keep its shape in the oven.

When ready to put the dough in the oven pre-heat it to 180ºC/160ºC. Whilst the oven is heating up, take out your baking tray from the fridge and remove the cling film. Using a skewer (or a fork) poke holes all the way through the dough at regular intervals. If you want to make really neat pieces then I suggest cutting shapes into the mixture at this stage so that you know where the holes should be. The pieces shown in the photos were 2.5cm wide, 2cm tall and 8cm long.

Put the baking tray with the dough in the oven. It takes 18-25 minutes to bake, depending on how long you have put the dough in the fridge for (the longer in the fridge the longer in the oven). The sides should be turning golden, but the middle will still be pale when it is ready to take out.

Once out of the oven leave to cool in the baking tray for 10-15 minutes. Then cut the shortbread into the shapes you want. If you already cut the shortbread into shapes before putting in the oven, just re-cut whilst still warm as some of the pieces may have partially joined back up again. Move the biscuits to a cooling rack until completely cooled.

Finally sprinkle some caster sugar over the top.