The lamb shank (Zeroa) is a crucial component of the seder plate, a reminder of the Korban Pesah (Paschal Lamb) sacrificed when the Israelites left Egypt, and for generations to follow, as long as the Temple was standing. Families gathered the first night of Passover to feast on the sacrifice of roasted lamb. Most Jews place a shank bone on the seder plate, to fulfill the memory of the sacrifice, which itself is forbidden in the absence of a Temple. Many take care to omit all roasted fare from their meal, in the spirit of the prohibition against the Paschal lamb in the Diaspora.
Syrian Jews have a fascinating custom that seems to defy Passover conventions. We start off our Seder meal (Shulhan Arukh) with lamb! In keeping with the interdiction, the lamb must be boiled, and not roasted, as the primary method of cooking, and may not be noted as being eaten in remembrance of the Paschal Lamb (Yalkut Yosef Volume 5: pp. 406- 7).
The traditional recipe, passed down to me by my grandmother, calls for boiling the lamb, then continuing to brown it in the oven. The tender meat is then stripped from the bone, which is reserved for the seder Plate. The delicate lamb morsels, gently warmed and served with lemon and allspice, disappear before the soup makes it to the table! In this recipe, pickled lemons add a kick that cuts through the richness of the lamb, and the addition of quinoa elevates it from an appetizer to a main dish (you can substitute rice for the quinoa if your custom is to eat rice on Passover). If your guests are not quite ready for lamb at the Seder table, this makes a delectable one dish meal for another Passover night!