Peel and finely chop the onion. Clean and wash the zucchini and cut into very fine strips. Heat the fat in a pot and fry the onions. Sprinkle with flour, sweat and deglaze with wine and chicken soup while stirring. Bring to the boil. Cut cheese into pieces and melt in the soup while stirring. Bring to the boil and season with salt, pepper and sugar.
Add zucchini and simmer for 2-3 minutes. In the meantime whip cream until semi-stiff. Wash basil, dab dry and pluck leaves from the stalks. Put some leaves aside for garnishing. Cut remaining leaves into strips and stir into the soup. Serve the soup with some cream. Serve with the rest of the basil and sprinkled with pepper