Though it's now a year-round favorite, this tender-crisp, butter-rich cookie was once associated mainly with Christmas and Hogmanay (Scottish New Year's Eve). The traditional round shape comes from the ancient Yule bannock, which was notched around the edges to signify the sun's rays. The classic way of making shortbread is to press the dough into a shallow earthenware mold that is decoratively carved. After baking, the large round cookie is turned out of the mold and cut into wedges. Today, more often than not, shortbread cookies are formed into simple squares or rounds.
From The Food Lover's Companion, Fourth edition by Sharon Tyler Herbst and Ron Herbst. Copyright © 2007, 2001, 1995, 1990 by Barron's Educational Series, Inc.