Clean the mushrooms, wash them if necessary. Peel and halve onions and cut them into thin strips. Dab schnitzel dry, cut into strips.
Heat the oil in a frying pan. Fry the escalope strips for 3-4 minutes. Season with salt and pepper. Put into an ovenproof dish.
Melt the butter in the frying fat. Fry the mushrooms and onions for about 5 minutes. Season with salt and pepper. Put them into the form and mix with the escalope strips.
Preheat oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3). Mix cream, chilli sauce, some salt and cayenne pepper. Pour over the casserole. Grate the cheese over the casserole.
Bake in a hot oven for 30-35 minutes. Wash parsley, shake dry, cut into strips and sprinkle over the finished casserole. Serve with farmhouse bread.