1 stick (4 ounces) cold unsalted butter, cut into small pieces
2 to 4 tablespoons ice water
In the bowl of a food processor, pulse the flour, salt, and sugar until combined. Add the butter, and pulse until the mixture resembles coarse meal, with larger chunks of butter remaining. Drizzle 2 tablespoons of ice water over the mixture and pulse until it just comes together without being wet, sticky, or crumbly. Do not over mix. If the dough doesn’t hold together when pinched between your fingers, add another tablespoon of water and pulse.
Place the dough on a large sheet of plastic wrap. Shape the dough into a disk, wrap well in the plastic, and chill in the fridge until firm, at least 1 hour or up to 3 days. Make ahead and freeze, well wrapped in plastic, for up to 2 months. Defrost in the fridge overnight. The dough is now ready to be rolled out and baked.
The ingredients need to be very cold. Cold ingredients mean flaky texture. Also, you should avoid overworking the dough and making it tough.