Cover the dough balls with a damp cloth, dust the worksurface with potato starch, and, working one at a time, roll the dough to make a very thin round, about 10-12cm wide.
Keep spinning the dough to get it to an even thinness. To make a neat circle, cut the dough with an 8cm round cutter. Keep the trimmings under the cloth to re-roll later on. Repeat with the remaining dough, keeping them under the damp tea towel as you go, with a sprinkling of potato starch in between each one. You can wrap these in clingfilm and freeze at this stage.