Sardines en Escabeche with Red Onion, Tomato, and White Wine

You’ll find pickled fish (sardines, mackerel, tuna, and, in summer, various “blue” fish) all around the Mediterranean. This recipe, pleasantly pungent with some dried hot pepper and white wine vinegar, is based on a pied-noir (French Colonial) dish I ate in Oran in the early 1970s, similar to recipes prepared in southern France and Spain. All are based on simmering whole fish in a strong medium, then boning and leaving them to marinate in the same liquid. A lengthy pickling gives bes