Bring the fresh or frozen mushrooms to the boil with the vegetable stock and let them steep for approx. 10 minutes. Strain the mushrooms, save the brew, do not pour away.
Make a light-colored roux from butter and flour and slowly pour in the stock until the stock is creamy. Always stir well to avoid clumping.
Add the mushrooms again and season with salt, pepper and vinegar (depending on your taste). Finish with cream and parsley. In addition, bread dumplings are served.