In a large bowl, whisk the flour, cornmeal and salt. Using a pastry blender or 2 knives, cut int the butter until the mixture resembles coarse meal. Drizzle in the ice water and lightly mix the dough with your hands just until it holds together. Divide the dough in half; pat into 2 disks and wrap well in plastic. refrigerate or freeze until ready to use. Let stand at room temperature until cool but malleable before rolling out.