In a large bowl, whisk together the gluten-free flour blend, sugar, xanthan gum and salt.Tip: If you're working in a very warm kitchen, you can chill the bowl and your combined dry ingredients in the fridge for about 30 minutes before starting. This will reduce the chances of the butter getting too warm and soft when you make the pie dough.

Add the cold cubed butter and toss it in the flour until each piece is coated.Tip: Make sure that your butter is COLD, straight out of the fridge.

Squish each cube of butter between your fingers to form small, thin sheets of butter. Once you’ve squished all the butter pieces, toss them again with the flour to ensure that they’re evenly distributed. Be sure to check that you’ve squished all the butter pieces before adding the water.Tip: Keeping the butter pieces relatively large and in the form of thin "sheets" will make your pie crust extra flaky. See blog post for photos.

Add the cold water and mix well with a fork or rubber spatula until the dough starts coming together. After you’ve added all the water, the dough will still look very dry – don’t be tempted to add more.Tip 1: Make sure that your water is COLD, ideally straight out of the fridge.Tip 2: The amount of water listed in the recipe works perfectly for a wide range of shop-bought gluten free flour blends, as well as for the DIY blend that you can mix yourself recommended in this recipe. If you use a very different blend (with a very different composition), you might need to adjust the amount of water.

Gently squeeze and knead the dough, pressing it against the sides of the bowl, until it comes together in a shaggy ball with little-to-no dry patches (this can take up to 5 minutes). If absolutely necessary, and if after 5 minutes the dough still hasn’t come together, sprinkle a tiny amount of water on the most persistent dry patches.The final dough should hold together in a ball but will not look perfectly smooth or evenly hydrated. That’s perfectly fine, the flour in the dough will hydrate more evenly during the next refrigeration step.Tip: Because you leave the butter pieces relatively large, the dough is initially (quite unsuccessfully) kept together only by the added water, which is why it will look incredibly dry and crumbly. As you knead, however, small portions of the butter melt from the heat of your hands, helping the dough to come together.

Wrap the dough loosely in cling film and tap it with a rolling pin to shape it into an approximately 6x10 inch (15x25cm) rectangle (no need to be super precise about it). I find it easiest to do this by folding the cling film into a rectangle around the initial disc of dough, and then use the rolling pin to tap and push the dough into a rectangular shape within the confines of the cling film.Tip: By shaping the dough into a rectangle before chilling, you’ll make the subsequent rolling out and laminating steps easier.

Chill in the fridge for about 30 minutes or until the pie dough feels firm but not hard when you press down on it with your finger.

Tap on the chilled pie dough rectangle (along its length) with a rolling pin to make it more pliable.Roll it out into an approximately 6x18 inch (15x45cm) rectangle (no need to be super precise about it). Turn the dough so that a short end is closest to you. Brush off any excess flour and fold the dough as you would an A4 letter – the top third down towards the middle and the bottom third up over it. This is called a "letter fold".

Rotate the dough by 90 degrees (so that the open ends are closest and farthest from you). Roll out into a similar-sized rectangle and repeat the letter fold. For best results, complete a total of 4-6 letter folds (the more you do, the greater the flakiness). If the dough becomes too soft at any point, chill it in the fridge for 15-30 minutes before proceeding.

After the final letter fold, wrap the dough in cling film and chill it for at least 30 minutes or until needed. (If you chill it for longer than 1 hour before using, soften it for about 15-30 minutes at room temperature, so that it’s pliable.)

Use as instructed in the chosen pie recipe.This recipe makes enough pie dough for one 9 inch (23cm) double-crust pie or two 9 inch (23cm) single-crust pies.

Storage:The gluten free pie crust keeps well wrapped tightly in cling film for 1 week in the fridge or 2-3 weeks in the freezer. When you want to use it, allow it to thaw at room temperature before using. If you press down on it with a finger, it should leave an indentation – but it should feel firm, not too soft to the touch.