Peel and chop the onion and roast vigorously together with the minced meat in hot oil, stirring constantly. Cut the mushrooms and roast them. Sprinkle with flour, stir well and add the stock and wine. Season with salt, pepper, garlic and the herbs. Let the sauce simmer for about 6 minutes. Finally stir in the sour cream.
Boil the pasta in salted water until al dente, strain and drain well. Mix the pasta with the sauce and parsley and serve. Sprinkle with chives.