Wash and peel the potatoes and cut small balls out of the potatoes with a ball cutter. Use the potato cuttings for other purposes and cook the balls in boiling salted water for 10-12 minutes.
Clean and halve the mushrooms. Peel and finely chop the onion. Clean, wash and drain the celery and tomatoes. Cut the celery into slices except for some green. Halve the tomatoes, remove the seeds and cut the halves into cubes.
Bring the celery to the boil in the stock, cover and cook for about 5 minutes. Wash venison steaks and pat dry. Heat clarified butter in a pan and fry the steaks for about 4 minutes, turning them over.
Add the mushrooms and half the onions, fry briefly and season with salt and pepper. Pour on white wine and 125 ml water, cover and stew for about 5 minutes. In the meantime heat up fat in a pot and fry the remaining onions in it until they are glassy.
Add the tomatoes, braise briefly, then add the celery with about 100 ml vegetable stock. Bring to the boil and season with salt and pepper. Stir cream cheese and sauce thickener into the stock, bring to the boil again briefly and season with salt and pepper.
Arrange vegetables, potatoes and the steaks with the sauce on a plate. Serve garnished with celery green.