I had some some frozen herring fiillets in the freezer - well, I suppose they would be, wouldn't they? - so I improvised.
Slice 1 small onion (pickling size) into rings. Combine in a saucepan 100 ml of malt vinegar and 100 ml of water, and bring to the boil with 2 tsp of sugar and 1 tsp of pink peppercorns. For a more sour taste don't dilute as much. Turn down the heat and simmer gently until the onion begins to soften - about 4-5 minutes.
Add 2 smallish herring fillets (still frozen is fine) skin up and simmer on a very low heat for another 5 minutes. Leave to cool in the liquor for as long as you can resist.
I had mine with a potato and radish salad, tossed with 2 dstspoons of mayo to 1 tsp of horseradish sauce, and a tomato, diced carrot, and celery salad dressed with tomato ketchup blended with a classic vinaigrette.
