The butter must be cold and cut into small cubes. Rub the butter into the flour using the tips of your fingers as quickly and lightly as possible, lifting the mixture high above the bowl and allowing it to fall back to incorporate air and keep the mixture cool. Continue until the mixture resembles fine breadcrumbs.
Cold water must be used - colder than tap water. Chill water for up to two hours or add a few ice cubes to water and measure when well chilled. Use the minimum amount of water to bring the pastry together. The addition too much water will result in a tough pastry which will shrink excessively when baked.
As soon as the dough clumps together in lumps, stop mixing and quickly gather the paste into a ball with your fingertips. Knead lightly with fingertips, not the palm of your hand, as the palm is hot and will soften the butter in the dough, resulting in tough dough.
Always chill pastry for at least 20 minutes to relax the dough. This helps to give a tender finished pastry with minimum shrinkage.
Always use a cool surface for rolling pastry. A marble surface is excellent, while a stainless steel or wooden surface also gives good results. Allow chilled pastry to soften a little. This will prevent pastry from cracking during rolling.