1. Whirl together flour, sugar, and salt in a food processor. Add butter and pulse into pea-size pieces. Drizzle 2/3 cup very cold water over crumbs and pulse just until moistened.
2. Turn dough onto a work surface and gather into a ball, turning to combine any dry crumbs.
3. Divide dough in half, form each into a disk, wrap in plastic wrap, and chill at least 30 minutes.