Fish with Rhubarb Sauce

Spring marks the arrival of rhubarb at-the market and of Passover. Thus, it is not surprising that fish in sweet-and-sour rhubarb sauce appears on the Seder table in Greece and Turkey. The major difference between the preparations favored in the two countries is in the proportion of rhubarb to tomato. In Greece, one part rhubarb to two parts tomato rules, while in Turkey the proportions are reversed. The original version of this recipe, from the Jewish community of Rhodes, calls for swordfi