3 small rainbow trout, scaled and filleted (you can use another fish, but make sure to use an oily one)
350ml good quality white wine vinegar
2 bay leaves (fresh if possible; I had to use dried since my tree died in the snow)
1 tablespoon sea salt
1 tablespoon coriander seeds
2 good hefty pinches pink peppercorns
2 spring onions, cut into short lengths
Zest of 1 unwaxed lemon
Put all the marinade ingredients in a pan and bring to the boil. Leave to cool and check for tartness, you may want more sugar in which case add some and heat again.
Wash the fish fillets, pat them dry then arrange them in a shallow dish in one layer. Once the sousing liquid is completely cool, pour it over the fish making sure they are completely submerged. Cover and leave for 24 hours in the fridge.