Combine the flour, salt, and sugar. Put on a large cutting board and mix with your fingers to blend.
Put the frozen butter on top of the flour mixture and use a pastry cutter to cut the butter quickly into the flour until the mixture resembles coarse meal with some butter pieces as large as 1/2~inch.
Working quickly, gather the flour/butter mixture into a mound and, using your fingers, draw a trench lengthwise down the middle of the flour mixture. Sprinkle 1 tablespoon of the ice water down the length of the trench. With your fingers, fluff the flour so that it absorbs the water.
Redraw the trench and continue incorporating the ice water by tablespoons in the same way.
After you have incorporated 2~3 tablespoons of water, the dough should begin to clump together into large pieces. If there are any unincorporated flour areas, sprinkle them lightly with droplets of water and mix as before.
Gather the dough into a mass with the pastry scraper and the heal of your hand and push away from you. Repeat 3 times. Gather the dough into a flat disk and wrap tightly in plastic wrap. Refrigerate for at least 2 hours or overnight.