Since the Middle Ages, Italians have been lightly frying fish and onions in abundant oil, then sousing them in vinegar for a day or two before eating them at room temperature as a choice light meal or antipasto. The version eaten in and around Venice is known as fish “in saor” (which curiously does not mean “sour”: it is Venetian for sapore, or “flavor”). The best fish for this are oily ones such as sardines, though some fancy-pants restaurant chefs use more prestigious fish such as sole, even though these are drier and blander.
Jackie and I had a yen for fish in saor the other week; I’d hoped that the fishers at our farmers’ market would be selling mackerel, but I saw none (and sardines are usually too much to hope for in our Long Island waters). What I did see was lovely bluefish, full of flavor and not so delicate that it would be lost in this preparation. I bought three biggish fillets, which in the end were enough for, let me see, nine modest servings, some entailing second helpings.
I cut them crosswise into modest portions, four or five per fillet depending on size; salted and peppered them; then dusted them with flour before pan-frying them briefly in lots of olive oil – a good half cup (120 ml) – over medium-high heat. I did this in two batches: about 90 seconds or two minutes on the skin side, until golden and slightly crisp, then a scant minute on the other side (less for the thinner pieces from the tail end). They were cooked, but not overcooked: hot liquid would later be poured over them. I put them on a plate without blotting off any oil (every drop is precious in this dish).
Then, I lowered the heat to medium-low and added a large onion and a narrow-gauge carrot (not strictly correct in this dish, but I like it), both thinly sliced and seasoned with salt and pepper, to the same oil (which had taken on flavor from the fish). I cooked, stirring frequently, until the onions were limp and very lightly golden but not browned. I stirred in 1/3 cup (80 ml by volume) of white raisins (sultanas), 1/4 cup (60 ml by volume) of lightly toasted pine nuts and 1/2 cup (120 ml) of white wine vinegar, let it boil for just 15 seconds and checked for salt.
In a non-reactive dish, I layered the fish with the onion-vinegar mixture (still hot) and finished by pouring the remaining mixture and all its liquid on top. Once it has cooled it can be eaten right away, but it is best to keep it for a day or two before serving at room temperature: cover with plastic wrap and refrigerate until two or three hours before dinner time. It will almost certainly need a sprinkle of salt when dished up. It tastes of vinegar but isn’t vinegary: all that oil and the fish juices and the sweet raisins balance the acidity perfectly. And the flavor and texture of the fish are enhanced, not masked.
In Venice and thereabouts, this is most typically served either on a slice of bread as a snack or with soft white polenta as a first course. It was also terrific the way Jackie and I served it to guests, as a very light main course: with tiny newly-dug potatoes boiled and served with no butter or seasoning to interfere with their earthiness, and a few leaves of salad dressed only with good olive oil and crunchy salt (no vinegar or lemon juice: there’s plenty of tartness in the fish, and that’s a great way to eat salad anyway).
On subsequent days, we ate it in a more traditional way, on lightly crisped bread, which soaked up the sauce. We never got bored with it – and, indeed, look forward to having it again soon.