Cut the leek into rings and add to the boiling beef stock. Cook for about 20 minutes over medium heat.
Finely chop the onions and fry them vigorously together with the minced meat. Season the mince with salt and pepper.
Add the fried mince to the broth and cook for a few minutes.
Add processed cheese and let dissolve while stirring. Add white wine and kirsch and let everything boil (until alcohol has evaporated). Always stir well!