Sauté the onions and garlic in heated oil. Add the tomatoes and bring to the boil. Add the stock and simmer covered for 10 minutes. If the soup is too runny, stir in the tomato paste. Add red wine. Cut the cervelatwurst into pieces and add it as well. Simmer again for a few minutes and season.
If you like, the soup can be refined with a dollop of cream.