Preheat oven to 375 degrees F. Sift flour, measure, then sift again with cornmeal and salt. Mix in the butter until crumbly. Stir in 2/3 cup warm water; chill. Cut chilled dough into 16 to 20 equal pieces and roll each piece into a ball. Use a rolling pin on a floured surface to make thin rounds. Transfer rounds to a baking sheet lined with parchment paper. Bake for 5 minutes or until lightly browned. Cool and serve with soup. Flatbreads can be frozen or stored in the refrigerator.