This recipe was originally prepared for sailors at sea because the sauce preserved the fish over long journeys. Jews on the Iberian peninsula invented the practice of frying foods in oil and then preserving them in a vinegar sauce in order to observe the Shabbat prohibition against using fire on the day of rest.
- Rinse the fish and pat dry. Season lightly with salt and pepper.
- Place the flour in a 1-gallon plastic bag and season with 1⁄2 teaspoon of salt and a few grindings of black pepper. Add 2 or 3 pieces of fish to the bag and toss until they’re completely coated. Remove them from the bag and repeat with the remaining fish.
- Heat a 10-inch skillet over high heat for 20 seconds. Add the olive oil and heat for an additional 10 seconds. Add the fish and fry until lightly golden brown on both sides (a total of 3 minutes per fillet or sardines and 4–5 minutes if using other small whole fish). Drain on a paper towel and then place the fish in a glass or porcelain casserole. Set aside to cool.
- Heat a sauté pan on high for 20 seconds. Add the olive oil and heat for 10 seconds. Reduce the heat slightly if the oil begins to smoke.
- Add the thinly sliced onions, sautéing until they’re soft and lightly golden. Pour in the vinegar, honey and saffron (if using), and raisins. Cook over moderate heat for approximately 5 minutes, until the mixture has reduced slightly.
- Lightly roast 1⁄4 cup of pine nuts in a 350°F oven for 4 minutes. Add them to the onion mixture, then remove the pan from the heat.
- When the onion mixture is warm to the touch, spoon over the fish.
- Either serve immediately or, for best flavoring, marinate in the refrigerator 1–2 days.
- Taste your raisins before making dishes with raisins and honey. Honey may not be needed if the raisins are wonderfully sweet.