Peel the onion and cut into thin strips. Also cut the radishes into thin strips and mix both in a bowl.
Bring the stock to the boil and mix with the balsalmico, mustard, oil, salt, pepper and chilli, add to the radishes and onions.
Now wash the raw, unpeeled potatoes and cut into approx. 2 mm thick slices. Fry them in clarified butter until crispy and add to the vinaigrette. Mix in well with the parsley.
This goes well with fish or delicious neck steak, etc.