Sarde in Saor (Venetian Sweet-Sour Sardines — Centuries-Old Preservation)

Ingredients

• 600 g fresh sardines (or small mackerel), cleaned and filleted (or 400 g frozen sardine fillets, thawed)
• 200 ml white wine vinegar (5% acidity)
• 150 g yellow onions (3 medium), thinly sliced
• 100 ml extra-virgin olive oil (Ligurian or Tuscan)
• 30 g sultana raisins (or currants), plumped briefly in warm water
• 30 g pine nuts (lightly toasted)
• 3 bay leaves (fresh if possible)
• 2 cloves garlic (thinly sliced)
• 1 teaspoon black mustard seeds (optional, traditional)
• 4 g fine sea salt
• 1 g white pepper

Method

1. 1
   Pat sardine fillets dry with absorbent paper; layer them in a non-reactive (ceramic or glass) dish, sprinkling lightly with fine sea salt between layers.
2. 2
   Heat 60 ml olive oil in a heavy-bottomed pan over medium heat; add thinly sliced onions and cook gently for 5–6 minutes, stirring, until softened but not coloured.
3. 3
   Add garlic slices and cook for 1 minute until fragrant; pour in white wine vinegar and bring to a bare simmer, then remove from heat and allow to cool slightly.
4. 4
   Add raisins, toasted pine nuts, bay leaves, mustard seeds (if using), and remaining 40 ml olive oil to the warm vinegar mixture; season with white pepper and stir to combine.
5. 5
   Pour the warm marinade and onion mixture over the layered sardines, ensuring they are submerged completely; cover loosely and allow to cool to room temperature.
6. 6
   Cover tightly and refrigerate for a minimum of 2 days (flavour improves over 3–5 days) before serving; the acidity of the vinegar and the oil will preserve the sardines, and they will keep refrigerated for up to 3 weeks.
7. 7
   Serve cold or at room temperature as part of an antipasto, dressed with a small drizzle of the pickling liquid, crusty bread alongside.