Wash the potatoes and cook in boiling water for about 30 minutes until soft. In the meantime wash, clean and quarter the tomatoes. Wash cucumber and cut into small cubes. Peel and finely dice the onion. Put chick peas in a sieve and drain.
Wash the parsley, shake dry and chop the leaves into small pieces, except for a stalk for garnishing.
Heat the oil in a frying pan. Sauté the onions and about half of the chickpeas in it for about 3 minutes, season with salt and pepper, deglaze with vinegar and place in a bowl. Use the rest of the chickpeas for other purposes.
Add tomatoes and cucumber, season to taste.
Grate cheese. Drain potatoes. Cut each potato lengthwise. Loosen the inside a little bit with a fork. Spread butter and cheese on the potatoes and mix lightly with a fork. Arrange the potatoes on plates.
Spread 1 tablespoon of chickpea salad on each potato and add 1 teaspoon of sour cream to each potato. Garnish with parsley. Add the remaining sour cream and salad.