Weigh the onions or shallots finely. Finely slice the mushrooms. Weigh the parsley finely. Cut the meat into strips and mix with the flour.
Let the butter with the oil get hot. Sear the meat vigorously in the pan, then add the shallots and mushrooms.
Season with salt and pepper, deglaze with wine and reduce this by half. Pour on the light veal stock and the cream. Let it boil down to the desired consistency. Season the dish with lemon juice, salt and pepper and serve sprinkled with parsley.