Boil the potatoes into jacket potatoes the day before (depending on size 35 - 40 minute fork test), let cool, peel and only cut into slices the next day so that they do not fall apart so easily.
Peel the lower third of the asparagus and cut off the ends. Then cut into pieces about 3 cm in size and cook in a little vegetable stock for about 6-7 minutes, drain.
Fry the onions in a little olive oil until they take on a little color.
Make a dressing from the remaining ingredients. Please add to the approximately information according to your taste. It`s best to mix everything in a shaker.
Then mix the dressing with the potatoes, asparagus and onions and chill for at least 1 hour. Mix again before serving and season to taste.