Its also rethinking Jewish foods for a younger generation-with frozen challah and rugelach, and a food truck serving up hot dogs and matzo ball soup. For the next ten days, while everyone else is settling back into school and ushering in autumn with pumpkin spice lattes, Jewish Americans will be celebrating the Days of Awe, starting with Rosh Hashanah, the Jewish New Year, and ending with Yom Kippur, the holiest day of the Jewish calendar.