2 salted herring fillets
The same quantity of pickled beetroot and sour apples
Salt and ground white pepper
1/2 pickled ridge cucumber
Soak the herring fillets to remove the surplus salt, and place them in the cucumber vinegar.
Leave for 18-24 hours.
Cut the herrings and beetroot and sour apple into fine strips.
Flavour the mayonnaise with the spices, the cucumber (mashed through a parsley mill) and the beetroot vinegar.
The mayonnaise should be just thick enough to bind the filling, and very strongly spiced.