Sauté onion, carrot and celery in oil until translucent. Add paprika, potatoes and cabbage and sauté until paprika is fragrant (approx. 1 minute) then pour in stock.
Bring soup to boil then reduce heat and allow to simmer.
In the meantime make a roux by melting the butter in a separate pan and whisking in the flour over a low heat to form a paste. Pour one cup of the soup into your roux and whisk together then pour the roux into your soup.
Allow to simmer for another 10 minutes then add caraway seeds and parsley. Serve with sour cream