Peel the onion, potatoes and carrots. Finely dice the onion, cut the carrots and potatoes into pieces. Heat the oil in a pan, sauté the onion, carrots and potatoes and then deglaze with hot soup. Season with salt, pepper and caraway and simmer for approx. 20 minutes until the vegetables are al dente. Stir occasionally. Roughly chop the parsley. When the vegetables are cooked, stir in the mascarpone and flavour the stew. Serve garnished with parsley.