Clean the mushrooms and cut them into slices. Beat the whipped cream until stiff and finely chop the chives.
Melt the butter in a saucepan. Peel the onion, cut into small cubes and bleach in the butter. Now dust with the flour and sweat briefly until light. Add the vegetable stock and mushrooms and cook for about five to ten minutes while stirring. Season to taste with salt and black pepper. Stir in the whipped cream and chives and serve immediately.