Melt the butter in a saucepan and sauté the onion and savoy cabbage for 5 minutes. Add the potatoes and 1 liter of water, as well as salt, pepper and caraway seeds. Bring the water to the boil and cover the vegetables for about 15 minutes. Then puree the soup. Stir in the parmesan and cream.
The soup can be served with parsley, croutons and very finely chopped spring onions. I used part of the soup as noodle soup. This is possible due to the creamy consistency.