Halve the herrings and cut into pieces approx. 2 cm in size. Mix with the white beans.
For the marinade, mix the sour cream with the yoghurt. Add the finely chopped pickles, as well as the finely chopped onion and capers. Season to taste with vinegar, oil, salt, pepper and a little sugar.
Pour the marinade over the pegs, mix well and let sit in the refrigerator for at least two hours before you can eat them.
Boil the potatoes in their skins. Then peel and cut into slices. Serve together.