Heat butter is a 2-quart saucepan and sauté onion over medium heat until golden. Add garlic and sauté for 1 minute.
Add chicken stock, tomatoes, tomato paste, basil and sugar. Bring to a boil and then reduce heat. Cover and simmer for 10 minutes.
Transfer soup to a blender and blend until smooth. Return soup to the pan and add cream and Parmesan cheese.
Taste and adjust sugar, salt and pepper to taste. Serve hot, garnished with additional chopped fresh basil. Makes 2 1/2 cups.