Kippers with horseradish cream

1) Heat the butter in a frying pan with a small splash of water and cook the kipper fillets skin-side down for approximately 4 minutes.
2) Meanwhile, in a small bowl, mix the crème fraîche with the horseradish. Add the vinegar and mustard and mix thoroughly.
3) Butter the slices of bread and put them on serving plates.
4) After the fish has been cooking for 4 minutes, turn the fillets over and fry for a further minute.
5) Remove the fish from the pan and place on top of the bread. Add a couple of spoonfuls of sauce and serve.