Begin by mixing the dough. Sift flour into a bowl, add water, salt, vinegar and melted butter.
When forms a soft ball, wrap this in cling film and refrigerate for 30 minutes.
Incorporate/fold the butter into the pastry by, rolling out and wrapping around a slab of butter.
Or, sift the flour and salt onto cold cubes of butter. For a deliciously rich pastry, use an equal weight of butter and flour.
Cut the butter into the flour. Using a pastry scraper or a large chef's knife, work until you have a crumbly mixture. Flatten any large chunks of butter with just your fingertips.
Add the ice-cold water a little at a time to bind the dough loosely. Mix the dough with the pastry scraper until it just hangs together.
Shape the messy, shaggy dough into a rough rectangle and roll it out until it's 1/2 inch thick. Resist the temptation to overwater or overwork the dough; it will eventually hold together. The dough is then repeatedly rolled, folded, and turned.
The goal is to distribute the butter evenly in sheets throughout the dough.