Matzo is an unleavened bread that is essential to the celebration of Passover. In Jewish tradition, the eating of the matzo represents the exodus from Egypt. Since the Israelites left in such a hurry, there wasn't enough time for the dough to rise. You can still buy matzo outside of Passover to use in matzo ball soup, as an alternative to bread crumbs or as an easy dessert. You can even turn to Food & Wine's guide to learn how to make your own matzo from scratch.