Wash the potatoes and cook in salted water for about 20 minutes. Then rinse with cold water and remove the skin. Let it cool down a bit. Meanwhile hard-boil the eggs, also rinse with cold water,
Clean the radishes, wash them and cut them into thin slices. Cucumber also wash and cut into slices. Wash and sort spinach and pluck into bite-sized pieces. Peel and finely chop the onions.
Cut the potatoes into slices. Season vinegar with salt and pepper. Add chopped onions and heat up in a pot. Pour over the potatoes while still hot. Fold in remaining prepared ingredients.
Cover and leave to soak for at least 30 minutes. In the meantime, wash the dill and chop finely, except for a bouquet for garnishing. Mix with mustard and oil. Pour over the salad. Season again and serve garnished with dill.