Cut the sticks of butter lengthwise into quarters. Slice the quarters crosswise into cubes and refrigerate. In a bowl or on a work surface, combine the flour and salt. Stir in the water with your fingers or a wooden spoon until the water disappears. Don't overwork the dough - it should look ragged.
Add the cold butter, form the mixture into a mound on a work surface, and pound it with a rolling pin until it is about 6 by 18 inches. Give the rolling pin a little twist at the instant it comes in contact with the dough while you’re pounding to keep the pieces of butter from sticking. If the butter starts to soften, refrigerate for 15 minutes.
Fold in the 2 ends of the rectangle so they meet in the center and fold again to form a packet with 4 layers of dough. The dough now has 1 double turn. If the dough felt elastic as you were rolling, refrigerate for 30 minutes, covered with plastic wrap, before continuing.
With the large single fold, like the spine of a book, on your left, roll the dough into a 6 by 18-inch rectangle. If at any point the butter starts to soften, melt, or stick to the work surface, refrigerate the dough for 20 minutes. Fold the rectangle as before, into 4 layers. This is the second double turn; mark the dough with 2 fingers to show it has had 2 double turns.
Refrigerate for at least 20 minutes. Repeat the rolling and folding once more for the third turn. If you need the pastry to puff rather than just be flaky, give it 1 more double turn. Refrigerate the dough, wrapped in
plastic wrap, for at least 1 hour before rolling out and baking.