Heat olive oil in a large Dutch oven over medium-high heat. Add onion, and sauté 4 minutes or until tender. Add water and next 7 ingredients (water through broth), and bring to boil. Cover, reduce heat, and simmer 5 minutes or until zucchini is tender.
Stir in pesto and tortellini; cover and simmer 6 minutes or until thoroughly heated and pasta is tender.
Changes I made: I added 2 cups chopped, cooking chicken. I used fire roasted tomatoes. I added extra garlic. I used chicken broth instead of vegetable broth. I used homemade pesto. It was good, but even with my changes a little bit bland. I bet the leftovers tomorrow will be more flavorful. The family enjoyed it and it was super easy to put together. Will make again.
I thought this was a very good soup. I used all fresh vegetables; spinach, carrots, mushrooms, zucchini, sauteed them all together. The soup was quick, easy, and comforting. I sprinkled a little parmesan cheese on top of each serving. I will make again, though wouldn't serve it to company.