Quarter the savoy cabbage, remove the stalk and cut the savoy cabbage into fine strips. Peel the carrots and cut into thin slices. Dice the vegetable onion, cut the mushrooms into slices and finely chop the parsley. Grate the cheese. Parry the meat and cut into even slices (3 medallions per person).
In a large saucepan, fry the onions with the carrots in hot oil. Scatter the brown sugar over the vegetables and stir briefly. Then add the savoy cabbage and fry briefly until it collapses. Deglaze with cream, sour cream and vegetable stock, season with salt and pepper. Let simmer on a low flame for about 15 minutes.
Fry the fillets in portions in hot oil for only 1 minute on each side and then remove from the pan, season with salt and pepper. Fry the mushrooms in the frying fat and season with salt and pepper. Sprinkle with parsley and remove the pan from the heat.
Spread the vegetables in a baking dish. Place the fillets on top. Spread the mushrooms on the meat and sprinkle the cheese on top. Bake in a preheated oven (175 degrees fan-assisted) for about 20 minutes.
It goes well with roasted or baked potatoes (see my recipe).