Wash the potatoes and cook in boiling water for about 20 minutes. Drain potatoes, rinse and peel.
Fry the meat in portions in a frying pan for about 5 minutes while turning.
Wash the cucumber and cut 2/3 into pieces. Clean, wash and cut the tomatoes into pieces. Peel onion and chop roughly. Cut potatoes into slices. Wash herbs, dab dry and, except for some marjoram for garnishing, pluck leaves from the stems and chop coarsely. Clean the pepperoni and cut into pieces.
Place all ingredients in a bowl. Mix yoghurt, oil and milk. Grate the remaining cucumber finely and add to the yoghurt. Season with salt, pepper, thyme and marjoram. Mix the sauce with the salad ingredients and let it soak through well. Season to taste again. Arrange the salad on plates. Crumble the cheese and pour over the salad. Garnish with marjoram and possibly pepperoni.