1. Pulse flour, cornmeal, salt, and sugar in a food processor until combined. Add butter, and pulse until mixture resembles coarse crumbs with some larger pieces remaining, about 10 seconds. Drizzle 1/4 cup ice water evenly over mixture. Pulse until mixture just begins to hold together when pressed between 2 fingers (it should not be wet or sticky). If dough is too dry, pulse in water, 1 tablespoon at a time.

2. Divide dough in half. Wrap in plastic. Shape into disks, and refrigerate until firm, about 1 hour or overnight.