Rollmops

Method

1. Dissolve 20 g of fine sea salt in 200 ml of cold water in a bowl. Slide in 2 herring fillets so they are fully submerged, cover and refrigerate for 3 hours to firm the flesh and season it through. Lift out, rinse under cold running water and pat completely dry on kitchen paper.
2. Put 100 ml of white wine vinegar, 100 ml of water, 1 tsp of caster sugar, 1 tsp of yellow mustard seeds, 6 black peppercorns, 3 allspice berries, 3 juniper berries and 1 bay leaf into a small non-reactive pan. Bring to the boil, simmer gently for 3 minutes, then take off the heat and leave to cool completely — a warm marinade will cook the fish.
3. Peel 0.5 small onion and slice it into rings about 2 mm thick. Quarter 1 large gherkin lengthways into batons.