Cut the schnitzel into strips and roll them in flour. Fry quickly in hot oil and remove from the pan again.
Pour the butter into the roast residue and sweat the onion in it. Add the tomato paste and roast until it turns a light brown color. Deglaze with white wine and the broth and let it simmer over high heat for about 10 minutes. Add the meat and cream and let it steep a little over a low heat. Season with salt and pepper and serve with croquettes or rice.