Peel an onion and a parsley root, cut into stripes, coat with vinegar or bouillon, add spices and boil for 10 minutes. Cool and combine with butter.

Halve the herring fillet lengthwise, make rolls, putting piece of pepper inside, place tightly on a non-oxidizing dish, coat with the marinade and put in the refrigerator for 6-8 hours.

Put on a plate, decorate with greens and the pickled onion when serving.