Remove the heads, guts and backbones from each anchovy. Butterfly them and rinse thoroughly under very cold running water.
Freeze the cleaned anchovies at –18 °C for 48–72 hours, then thaw slowly in the fridge.
Spread a generous layer of coarse sea salt over the thawed anchovies. Leave to rest for 30 minutes, then rinse off the salt and pat dry with kitchen paper.
In a glass or plastic dish, arrange the anchovies skin-side up.
In a bowl, combine the white wine vinegar and cold water. Pour the mixture over the anchovies until they’re completely submerged. Cover and chill for 6–8 hours, or ideally overnight.
Drain the anchovies in a colander, pressing down gently to remove any excess liquid.
Finely chop the garlic cloves and fresh parsley.
Arrange the drained anchovies on a serving platter. Sprinkle over the chopped garlic and parsley, then drizzle generously with good-quality extra virgin olive oil.
Allow the anchovies to marinate in the oil and herbs for at least 30 minutes before serving. Serve with olives, crisps or crusty bread, if you like.