Peel and chop the onion. Clean the mushrooms and cut into slices.
Briefly sweat the onion in 1 tablespoon of butter and 1 tablespoon of olive oil, add the mushrooms and fry them. Season with a little salt and pepper and continue to fry until they have turned slightly color. Add the tomato paste and sweat briefly. Sprinkle with the flour and then brown a little. Deglaze with the broth and bring to the boil. Add the cream and simmer on a low flame for about 20-30 minutes.
Wash the schnitzel, pat dry and season with salt, pepper and cayenne pepper. Fry in a little clarified butter or oil for about 2-3 minutes on each side, remove and place in a baking dish.
Pour the sauce over it, cover with a slice of cheese and place in the oven at 180 ° C until the cheese has melted.