Middle Eastern Tomato-Rhubarb Sauce for Fish

I know this sounds weird, but trust me—it is a delicious sweet and sour sauce for fish. In Greece and Turkey, this recipe is traditional at Passover. In Greece there are two parts tomato to one part rhubarb; in Turkey, the proportions are reversed. To keep the peace, this version has equal amounts of tomato and rhubarb. While the sauce usually is served at room temperature, it’s also delightful spooned warm over the cooked fish. Swordfish, sea bass, cod, flounder, and salmon are excellent c