On a lightly floured surface or between two sheets of parchment paper, roll out one disc of plain cookie dough at a time into a 30 x 23-cm (12 x 9-inch) rectangle, about 5-mm (¼-inch) thick. Do the same with cocoa and cinnamon cookie dough discs. Layer 2 sheets, one with each dough. Roll a cookie log from the longer side.
