Wash the potatoes, cook them al dente with plenty of salt, drain and steam.
During this time, peel the onion and garlic, cut into fine rings, sweat in a little vegetable oil and deglaze with four to five tablespoons of vinegar. Cut the apple into small cubes and add to the onions.
Peel the still warm potatoes and cut into approx. 4 mm thick slices. Now carefully mix the potatoes, onions, yoghurt, mayonnaise, lovage and season to taste.
Let the salad stand for about 20 minutes, then season to taste again and serve at room temperature.