Fry the onion in olive oil for 10 minutes over a low heat.
Put the water, beetroot and potato in a large covered pan, bring to boil, reduce the heat and simmer for 10 minutes.
Add the cabbage to the onion, and cook for 5 minutes. Add the wine and cook for 2-3 minutes
Blend the potato and beetroot until smooth, then add the onion and cabbage and season. Serve with a blob of crème fraîche and freshly chopped chives.