These these mildly sweet, crisp biscuits — called biscochos de susam, or sometimes just biscochos have their roots in pre-Inquisition Spain. They have become a hallmark of Sephardi cuisine — Middle Eastern Jews bake a similar cookie called kaak. Biscochos are served on Rosh Hashanah (the ring shape symbolizes hopes for a full and round year to come) and also to break the Yom Kippur fast.
 

Recipes adapted from The Jewish Cookbook