Peel and slice the onion. Peel, deseed and slice the apple. Wash the red cabbage, quarter, remove and discard middle part, and cut into stripes.
Melt butter in a large pot. Add onion and apple and fry for 3 minutes, stirring frequently. Add the cabbage and cook for a couple of minutes. Keep stirring. Add cranberry jam/sauce/chutney, red wine, vegetable stock, bay leaf and juniper berries. Cover with lid and cook on low heat until vegetable is done. This will take about 40 minutes.
Remove and discard bay leaf and blend soup. I always use a big pot and blend my soup in the pot with my hand blender.
Add additional water or stock if desired. Cook for another 3-4 minutes. Add balsamic vinegar, salt (if necessary), and pepper. Remove from heat and add cream. Depending on the fat content of your cream, the cream may curdle if heated on high temperature. Check if soup is hot enough. If not, only warm on low heat, in particular if you use single cream!
SERVE: Ladle soup into warmed bowls and sprinkle with the additional walnut or olive oil. You may want to sprinkle your soup with some cream instead of the oil.