On Monday evening, many Jewish families and communities will gather for Passover's traditional Seder meal. Passover, which is a week-long holiday marking the Jewish exodus from slavery in Egypt, is a time when leavened bread is not eaten, since it’s believed that bread did not have time to rise during the flight from Egypt. Instead, matzo, a cracker-like unleavened flat bread, is often the center piece of a Passover Seder.