Defrost the peas. Wash potatoes and cook in boiling water for about 20 minutes. Drain potatoes, rinse and peel. Let cool down a little. Wash dill, shake dry and chop finely, except for 4 flags.
Wash the cucumber, dab dry and cut into cubes. Mix horseradish, yoghurt and sour cream, season to taste with salt, pepper and a little sugar. Quarter the potatoes and put them in a bowl with cucumber, dill and peas.
Fold in sour cream. Let the salad marinate briefly. In the meantime peel the prawns and remove the intestines. Wash the prawns and pat dry. Peel and crush garlic. Wash thyme and dab dry.
Heat the oil in a frying pan. Gently fry the prawns, garlic and thyme for approx. 4 minutes, turning them over. Season with salt and pepper. Flavour salad with salt, pepper, sugar and horseradish. Arrange salad and prawns on plates, garnish with dill flags.