Finely slice the white cabbage, dice the potatoes and roughly chop the mushrooms. Cut the onions into slices and sauté in butter until translucent.
Grease a large, well-closing saucepan with butter and then layer in thin layers of white cabbage, potatoes, mushrooms and onions until all the vegetables are used up. Sprinkle salt, pepper and caraway seeds on every second or third layer.
Dissolve the vegetable stock in warm water and pour over the vegetables. Simmer gently for 30-40 minutes with a closed saucepan and low heat without stirring. Take off the stove and melt flakes of butter on it.