Put the flour and a pinch of salt in the food processor. Turn it on and steadily pour in 150ml of water. When the dough comes together, cover it in cling film and chill for 20 mins.
Lightly flour your surface and roll the dough into a 25cm circle. Put the butter in between two pieces of baking parchment and soften it by tapping it with a rolling pin. Cut the butter in half and repeat the process until the butter is pliable but still cold. Reshape to the size roughly of a postcard.
Put the butter in the centre of the pastry and fold over the right and left sides of the circle, overlapping in the middle. Press the dough with your rolling pin to make it longer and then lightly mark into thirds. Fold the bottom third up to cover the middle third and the top third down. Seal the dough gently by pressing down on the edges with your rolling pin. Give the dough a quarter turn.
Roll the dough out to a long rectangle (roughly 18 x 38cm), keeping the edges square and the sides straight. Mark the dough into thirds again, fold the bottom third up and the top third down. Seal the edges and give the dough a quarter turn. Repeat one more time, cover and chill for 20 mins.
Repeat step four twice more, chilling each time. Chill for one hour before using.
Watch our puff pastry video for a Good Food tutorial.