Mix the flour, sugar, baking powder, salt and xanthan gum in a large mixing bowl. Make a well in the centre and pour in 250ml warm water and the olive oil. Combine quickly with your hands, to create a thick, wet, paste-like texture, adding an extra 20ml warm water if the dough feels a little dry. Store in an airtight container or covered bowl in the fridge for up to 24 hours before using. Using the dough to make pizza? See the full recipe for gluten-free pizza.