1 (15-ounce) can low-sodium canellini beans, drained and rinsed
1 tablespoon olive oil
1/2 large onion, diced (about 1 cup)
2 carrots, diced (about 1/2 cup)
2 stalks celery, diced, (about 1/2 cup)
1 small zucchini, diced (about 1 1/2 cups)
1 clove garlic, minced
1 tablespoon chopped fresh thyme leaves (or 1 teaspoon dried)
2 teaspoons chopped fresh sage leaves (or 1/2 teaspoon dried)
1/2 teaspoon salt
1/4 teaspoon freshly ground black pepper
32 ounces low-sodium chicken broth or vegetable broth
1 (14.5-ounce) can no salt added diced tomatoes
2 cups chopped baby spinach leaves
1/3 cup freshly grated Parmesan, optional