You can easily change the recipe to a classic Tomato Basil soup.
Simply pour the soup you have into a blender,, (let's assume 4 or 5 cups of soup), add about a teaspoon full (small pyramid in your palm) of sugar, as others have suggested and about 14 to 16 fresh basil leaves. Blend until smooth and th eleaves are chopped to small but still recognizable pieces. Return the mixture to your soup pot and heat to warm and add about a cupfull (we're in the U,S. so I don't know...about 6 to 8 ounces) of heavy cream and bring to high heat, but not a boil. Simmer about 15 minutes and then add 1/2 cup (maybe 1 and 1/2 sticks) of fresh butter... heat another 10 minutes and stir in the butter well... Serve warm and add a fresh basil leaf as granish...