This basic Scottish butter shortbread is a simple three-ingredient cookie, but modern versions call for two types of sugar, salt, or small amounts of cornbread. The name comes from the fact that “short” was an old usage for the term “crumbly”: because of the high-fat content, the biscuit’s texture is indeed crumbly and crispy. The shortbreads can be shaped before or after cooking, and most traditional recipes call for discs, squares, petticoat tails (triangular pizza-shaped slices made out of a big circle), or thick rectangular fingers. Pat the shortbread into the pan or roll it and cut the dough in the preferred shape.