Peel the onions and peel the garlic. Cut both into cubes and fry in olive oil until they are golden yellow (if available, deglaze with a dash of red wine). Now add the tomatoes and cook for 5 minutes. After approx. 5 minutes add the sugar and cook for another 5 minutes. Now add the sour cream and simmer for another 2 minutes on a low flame. Now puree the whole thing with a hand blender to make a creamy soup. Season to taste with salt and pepper.
Sprinkle with chopped parsley before serving.
Tip: This soup also goes well with pasta! But then do NOT puree the whole thing.