- In a large saucepan, soften the celery, carrots, leek, onion, and garlic in the oil for about 5 minutes. Season with salt and pepper. Add the broth and tomatoes and bring to a boil. Cover and simmer for about 15 minutes or until the vegetables are tender.
- Add the zucchini, peppers, green beans, and white beans. Bring to a boil and cook for about 8 minutes. Adjust the seasoning.
- Ladle the soup into four bowls. Top with the sausage, pesto, and Parmesan cheese.