Caramelize the sugar and butter in the roasting set and briefly sweat the quartered plums, remove them and set aside.
Finely dice the onion, sauté in the roasting dish and deglaze with red wine, allow to reduce. Pour in the poultry or vegetable stock and add the fruits, bring to the boil briefly. Season with salt and pepper and add the balsamic vinegar and thyme.
Put the schnitzel in the sauce and, with the lid on, let it simmer for about 5 - 7 minutes.
Mix the cornstarch with a little water and use it to thicken the sauce. Arrange the schnitzel on the sauce mirror and serve with the caramelized fruits that have been set aside.
Noodles or boiled potatoes tossed in a little butter, sprinkled with fresh, finely chopped parsley, taste great with it. A fresh, colorful autumn salad tastes good with it.