Soak herring whole overnight. Remove skins and entrails. Filet herring and cut into pieces; or cut into slices through bone. Place herring in jar in layers alternating with sliced onions. Combine vinegar, water, sugar and sour cream. Pour over herring. Store in refrigerator for a day or two before serving.

If you like it sweeter, add more sugar; sour, add vinegar. If you wish, omit sour cream in the pickling liquid. Instead, add it to the drained, pickled herring when ready to serve. A tbs of whole pickling spice added to the marinade adds zest.