Fish Soup with Parsi-Style Rouille

During the heyday of the Julia Child cooking shows in the late 1960s, Gourmet magazine printed a marvelously simple recipe for a Provençal fish soup, aïgo sau, served with a sauce rouille. Like other favorites, it became etched in my memory—the idea behind it, if not the exact particulars. Aïgo sau inspired the following soup based on the seasonings for khari machhi, our mild Parsi fish stew, considered comfort food suita