Preheat your oven to 150C fan / 170C and prepare a couple of baking trays with non stick baking paper.

In a large bowl mix together the softened butter and sugar to combine. Then add the vanilla and mix once more - do this with a spatula, not a mixer.

Add the plain flour, cornflour and xanthan gum and mix once more with your spatula. It will be super crumbly, but once combined get your hands in to start bringing it together to form a ball of dough. It takes time, and you’ll think ‘it’s not coming together, it’s too dry’ - ignore that thought, just keep going for a few minutes.

Once into a smooth ball of dough, roll it out between two pieces of non stick baking paper to about 6mm thick. Cut out 5.5cm rounds using a cookie cutter and place them onto your prepared baking trays. They don’t really spread so huge gaps aren’t necessary. 

Sprinkle the dough circles with extra caster sugar and poke a few holes in the top. Make sure you re-roll your dough so you use it up.

Bake it the oven for around 18-20 minutes until cooked. Remember - we don't want any signs of browning! Allow to cool and enjoy!

OPTIONAL STEP: To create chocolate dipped shortbread, simply melt the chocolate in the microwave in short bursts. Then dip the cooled biscuits into the chocolate and allow to set on a cooling rack.