Knead the flour and softened butter with a fork. Clean the mushrooms and cut into slices. Finely chop the onion and parsley. Cut the chicken breasts into strips.
Reduce the poultry stock by approx. 1/3, let simmer for 5 minutes. Thicken with flour and butter, cook again and stir.
Heat the olive oil in a pan, fry the chicken breast strips, add onions and mushrooms and sauté and stir again and again. Then deglaze with white wine and add the bound poultry stock. Bring to the boil briefly, refine with creme fraiche, season to taste and sprinkle with parsley.