Have fun preparing this mushroom dish!
Sauté potatoes and leek in a little oil while stirring continuously, pour in clear soup and cook on low heat for about 15 minutes until soft. Remove from heat and mash – no longer than necessary, otherwise the potatoes will bind too much. Pour into a large enough bowl and leave to cool for about 8 hours.
Fry the chopped mushrooms in a little oil, drain well and cool. If desired, cook leek pieces al dente.
Mix soup with mushrooms, marjoram and leek pieces and ladle into precooled plates. Cut out dumplings from the mascarpone and garnish the soup with them.