Pulse flour, salt, and sugar in a food processor until combined. Add butter, and pulse until mixture resembles coarse crumbs with some larger pieces remaining, about 5 seconds.
Drizzle water evenly over mixture. Pulse until mixture just begins to hold together, about 10 seconds. (Dough should not be wet or sticky.) Press dough into 1 large disk (for mini pies) or 2 small disks (for large pie), and wrap in plastic wrap. Refrigerate until firm, about 1 hour or overnight.
Dough can be refrigerated for up to 2 days or frozen for up to 3 months. Thaw before using.