The amounts for butter, flour, and water are given by weight (ounces) and by volume (cups or tablespoons); use either measurement.
Sift the flour and salt onto the cold cubes of butter. Using a pastry scraper or a large chef's knife, cut the butter into the flour. 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 loosely bind the dough. 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.
Use the pastry scraper to fold the dough in thirds like a business letter. Don't worry if it folds in pieces. Turn the package of dough 90 degrees so the folds run vertically. Square off the edges of the dough as you work. Roll the dough into a rectangle that's 1/2 inch thick, always rolling from open end to open end. Continue rolling, folding, and turning until the dough looks smooth. By four or five "turns," the dough should hang together well.
For even more layers, fold the smooth dough up like a book. To do this, fold the two shorter sides into the center and then fold the dough like a book. Brush off excess flour as you fold. Wrap the dough and chill it for half an hour before giving it two final turns. At this point, you can then use the dough, though another short rest will make rolling and shaping easier.