Cover the potatoes and cook them in boiling water for about 20 minutes. Drain, quench, peel and let cool.
Peel garlic and chop very finely. Mash sheep's cheese finely with a fork. Stir in milk, sour cream and garlic. Season to taste with salt and pepper.
Wash and halve the tomatoes. Peel the cucumber, halve it lengthwise and cut into slices. Clean, wash and drain lamb's lettuce.
Cut the potatoes into slices. Peel and chop the onions and fry half of them in 1 tbsp. hot oil. Add vinegar and 100 ml water, stir in broth and simmer for 2 minutes. Pour hot over the potatoes, mix carefully.
Fold in sheep's cheese cream. Leave to stand for approx. 30 minutes.
For the meatballs, soak rolls in cold water. Knead minced meat, rest of onions, egg, mustard, squeezed out roll and 1 tsp. salt and pepper each. Form approx. 8 meatballs from the minced meat mixture.
Heat 2 tablespoons of oil in a large frying pan. Fry the meatballs on each side over medium heat for about 5 minutes. Fold the tomatoes, cucumber and lamb's lettuce into the potato salad. Season to taste with salt and pepper.