Combine drained peppers and diced tomatoes in a blender. Puree until smooth.
Heat oil in a large soup pot over medium heat. Add pepper-tomato mixture, tomato puree, chicken broth, sugar, salt and pepper. Heat just to simmering, about 8 minutes. Remove from heat and whisk in heavy cream. Return to stove and heat through. Ladle soup into bowls; top each with a few croutons.