In a large bowl, mix the flour and salt thoroughly. Cut the stick of butter into small squares, about a half-inch big. Add them to the flour and, using clean, cold hands, toss them gently to coat. Working quickly, work the butter into the flour with your fingers until the mixture begins to look like large breadcrumbs. (it is better to leave some streaks of butter in than to overwork the dough). Sprinkle the water over the flour a tablespoon at a time, and then quickly stir it in with you hand. Use light, quick strokes to keep the dough cool.
Continue to combine until the dough hangs together; add more water if necessary, but try not to add too much—you want just enough water to make it possible to roll the crust out without it falling apart, but no more.
At this point, you can wrap the dough in plastic wrap and refrigerate until you need it (take it out about 30 minutes before you roll it out). Or roll immediately: Lightly flour a clean, large work surface. Shape the dough into a puck and roll out into a circle until it’s about 1/8-inch thick. Brush any excess flour from the crust. Using the rolling pin, roll the dough over the pin lightly, brushing excess flour from the backside as you go; then transfer to the pie plate, draping it into the pan.
Trim the edges of the dough, leaving about an inch overhang. Then fold the edges under and crimp them. Refrigerate or freeze until needed.