Peel the potatoes and cook in water. Drain the water and let hem cool down.
Heat up the vegetable broth.
Finley chop the parsley and onion and cut the potatoes in thin slices, put it all in a bowl.
Mix the spices, mustard, oil, vinegar together.
Pour the broth and mustard mixture over the potatoes and mix gently several times for the next 30 minutes.