Venetian sweet-and-sour sardines (Sarde in saor)

1. Cut the heads off the sardines, slit open the bellies and remove the innards, rinse in cold water and pat thoroughly dry with kitchen paper; soak the raisins in lukewarm water.

2. Salt the fish lightly, dredge in flour, shake off the excess and fry in the hot vegetable oil in batches for 2 minutes per side until golden; drain on kitchen paper.

3. Slice the onions into thin half-rings and cook them in the olive oil in a frying pan over low heat, stirring often, for 15-20 minutes until soft and translucent (don't let them brown).

4. Pour in the white wine vinegar, add the sugar, season with salt and pepper and boil for 3-4 minutes; finally stir in the squeezed-out raisins and the pine nuts.

5. In a deep dish, layer the sardines and the hot vinegary onions alternately, finishing with onions, so that the marinade covers everything.

6. Leave to cool, cover and chill for at least 24 hours; take out half an hour before serving to come to room temperature.

Tip: Venetian fishermen once preserved fish this way for long voyages - saor is best after resting for 1-2 days and keeps for 4-5 days in the fridge.