Place half the dough on lightly oiled 17 x 14 inch baking sheet and roll out to edges (dough will be very thin). Use extra flour as needed to keep the dough from sticking to the rolling pin. Prick all over with a fork and cut in 1 1/2 inch squares. Bake at 400 degrees for 10 minutes or until crisp but not too brown. Remove to racks to cool. Repeat with remaining dough.