Boil the potatoes with their skin on. In the meantime wash the vegetables. Slice the cucumber and then cut it into fine strips. Cut the pepper into small cubes. Core the tomatoes and dice them too.
Put everything together in a bowl and add the quark. Stir well. Then add the spices and mix again. Now mix with plenty of dressing, some cream and a spoon of natural yoghurt. Now just season to taste.
Peel the potatoes and arrange on a plate with the quark. If you like, add a little butter to the potatoes.