Boil the eggs hard for approx. 10 minutes, quench, peel and let cool. Rinse the potatoes, cook until al dente, peel and let cool. Cut the potatoes into slices, dice the cucumber, onions and meat sausage.
Mix the mayonnaise with yoghurt, mustard, lemon juice and a little cucumber water, season with salt and pepper. Mix all ingredients in a large bowl. Dice 2 eggs, add and mix again. Cover and let stand for at least 2 hours (I let everything stand overnight).
Cut the tomatoes and the remaining eggs into eighths and garnish the salad with them, adding parsley if necessary.