Dice the butter and place it in the bowl of a food processor along with the flour and salt. Process for around 30 seconds until the mixture resembles breadcrumbs.
Transfer the mixture into a mixing bowl. Make a well in the centre and pour in your water. Using your hand like a whisk, twist and mop up all of the flour mixture and press the dough together.
Transfer the dough to a lightly floured surface and gently kneed the dough together. Cover with plastic wrap and refrigerate for at least 30 minutes before rolling out.