In a Dutch oven, saute the onion, potato and celery in oil until tender. Add garlic; cook 1 minute longer. Stir in the broth, beans, tomatoes, parsley and pesto. Bring to a boil. Stir in pasta. Reduce heat; cover and simmer until pasta is tender, 10-15 minutes. , Add spinach and cook just until wilted. Sprinkle each serving with cheese.