By cooking polenta longer, you will achieve a firmer mass - which can then be spread out, cooled, and cut into shapes that have a springy, resilient texture. There is a classic Northern Italian board, called a tagliere, on which the polenta is spread. But you can do it on any flat surface, or in a baking dish. The key question is: what thickness do you like in the finished product? We're partial to polenta cut-outs that are about 1/2 inch thick, so we spread our just - cooked polenta out into a large, smooth rectangle that's 1/2 inch thick. The polenta shapes may be cut out after a half hour of cooling, but the texture's much better if the slab is refrigerated for 24 hours.