Wash herrings thoroughly and dab dry. Mix flour, paprika and a little salt on a plate and roll the herrings in it. Heat the fat in portions in a pan and fry the herrings one after the other on both sides. For the stock, add vinegar, 1/8 litre water, bay leaf, juniper berries, pepper and mustard seeds, 1 teaspoon salt, pepper and sugar and bring to the boil. In the meantime peel onions and cut them into rings.
Leave to stand briefly in the hot stock until they are slightly tender. Put fried herrings in a large, flat form and pour the hot stock over them. Leave to infuse for at least 24 hours. Fried potatoes taste good with it