Wash the potatoes thoroughly, drain and cook in plenty of boiling salted water for about 15 minutes. Mix crème fraîche, horseradish, sugar and vinegar together. Season with salt and pepper
Rinse the crayfish meat with cold water on a sieve. Set aside. Wash and clean the cucumber and slice lengthwise into thin strips.
Drain, quench, peel and slice the potatoes
Wash the dill, shake dry and set aside flags for garnishing. Mix all ingredients. Sprinkle with dill, coarse pepper and sea salt