Finely dice the onions, garlic and carrot. Mix with the tomatoes, juice and cream in a bowl, chop the tomatoes. Season well with oregano, salt, pepper and a pinch of sugar.
Season the schnitzel with salt and pepper and place in a greased baking dish. Season the mince with salt and pepper. Spread on the schnitzel and press down lightly. Pour tomato sauce over it.
Braise in the oven at 175 degrees, circulating air 150 degrees for 1.5 hours. Make sure that the meat is well covered with the sauce. Possibly pour in some more broth.
Sprinkle the cheese over the schnitzel 20 minutes before the end of the roasting time.