 Challah is typically an egg-enriched bread, often braided in the Ashkenazi tradition, or round for Rosh Hashana, the Jewish New Year.The Shabbat and festival breads of the Yemenite Jews have become popular in Israel and can be bought frozen in supermarkets.Jachnun is very thinly rolled dough, brushed with oil or fat and baked overnight at a very low heat.