Hard boil the egg in boiling water for about 10 minutes. Quench under cold water and let it cool down. In the meantime cut cucumber into fine cubes. Wash the herbs, dab dry and chop finely. Peel egg and chop finely.
Stir salad cream, yoghurt, mustard and approx. 2 tablespoons of cucumber stock until smooth. Remove some of the herbs, egg and cucumber cubes for sprinkling. Stir the rest into the sauce. Season to taste with salt and pepper, place in a small bowl and sprinkle with the remaining sliced ingredients