Kidneys are washed well, then cut in two lengthwise and boiled. Once the water boils discard it, and with it the odor. Boil again in clean salted water until soft. Once cooked cut into thin strips.
The mushrooms are cooked separately, also in pieces, then sautéed in butter. Beat them and the kidney stew. Sprinkle flour and fry after pouring wine. After a few minutes, pour the broth from the mushrooms and kidneys.
All products are mixed and boiled for a few minutes. Serve in a warm dish, sprinkle with chopped parsley and pepper cooked with the sautéed potatoes.