Cut the butter (which must be as cold as possible!) into cubes of approx 2cm.

Add the gluten free flour, xanthan gum and salt to a large mixing bowl and stir. Then add the cubes of cold butter.

Using two butter knives, ‘criss-cross’ across the pastry mix, cutting the butter into smaller pieces. You'll want to keep stirring the bowl to make sure the cut edges become coated in flour. Keep going until the butter lumps are mostly the size of peas - a few bigger lumps are absolutely fine.

Sprinkle gluten free flour onto a worktop and place the ball of dough in the centre. Use your hands to flatten the dough slightly and shape it into a rectangle shape.

Roll the dough out in ONE DIRECTION only, in one long rectangle approx 1cm thick. I find the best way to do this is to roll the dough away from you. Use your hands to keep gently nudging the pastry back into a reasonably straight line on the edges. You should see marbled streaks of butter throughout the dough as you roll it.

Take the short edge which is furthest away from you and fold it back towards you until it meets the centre line. Then take the edge closest to you and fold it away from you over the piece you have just folded, so the pastry is in three layers.

Wrap in clingfilm and place in the fridge for 20-30 minutes until chilled. When you remove it from the fridge, place the dough down in exactly the same position as it was before, then give the dough a quarter turn clockwise.

Repeat steps 6, 7 and 8 TWICE more - so a total of three fold-and-turns. Each time you start, place the folded dough in the same position as when you finished the last fold and give it a quarter-turn before you begin rolling.