(*) for six to eight people:
Soak salted herrings in water for at least 24 hours so that they lose salt. During this time, renew the water twice. (Matjes herrings can be used on the spot.) Drain water. Skin and fillet the herrings. To do this, start by peeling off the skin from the head toward the tail, removing the dorsal fin along with it. Using a sharp knife, score the herring along the length of the back and the middle bone to a depth of 1 cm, run your thumb along the incision to detach the back fillet. Loosen the belly fillet from the center bone with a fine knife. Cut thin strips from the belly flaps into small pieces and discard, plucking any remaining bones from the fillets.
Cut each fillet into three pieces.
Peel onions and cut into thin slices. In a saucepan, bring the wine, vinegar and 100 ml of water to a boil with the sugar and spices until the sugar is dissolved. Add onions and make the mixture over medium heat for 2-3 min, then cool.
Place layers of onions and herring pieces in a large, well-cleaned jar, then pour the broth over them so they are covered. Let the herring steep in a cool place (not in the refrigerator) for 2-3 days. They will keep for about 2 weeks.
Tip: Salt herrings are available from the fishmonger from the barrel. If necessary, vacuum-packed herrings in 1-kilo packages from the supermarket are also suitable. They are gutted and without head, however, not yet