Zucchini-Spinach Soup

Zucchini and spinach are two vegetables that are relatively cheap and easy to find at the store, even in winter, so I'm making this soup from Caldwell Esselstyn's Prevent and Reverse Heart Disease to accompany Creamy Avocado White Bean Wraps (which I'm pretty sure will be tasty regardless of how this soup turns out).  Sameer doesn't tend to approve of sandwiches for dinner, so I try to make sure any I feed him are extra special sandwiches and either hot or served alongside something hot (such as this soup). 

Ingredients
9 medium zucchini (about 3 lbs), chunked
1 large onion, coarsely chopped (1 cup)
3 large garlic cloves, chopped
3 cups vegetable broth, or water, or a combination of wine and broth or wine and water (I'll be using broth or broth and some water.)
2 tbs miso, Bragg Liquid Aminos, or low-sodium tamari (optional) (I'll use Bragg's because I keep it on hand.)
8 oz (or more) fresh spinach, coarsely chopped, or 1 box or bag of frozen spinach
2 cups frozen corn
pepper, to taste

Directions

1. Combine zucchini, onion, garlic, and 3 cups of liquid in a soup pot.

2.  Bring to a boil, lower heat, cover, and simmer about 10 minutes until zucchini is tender.

3. Blend soup mixture with an immersion blender until smooth and a rich, green color.

4. Add miso, Bragg's, or tamari, if desired.

5. Add corn and spinach and any other vegetables you wish. Heat until corn and spinach are warm but not overcooked.

6. Add pepper to taste.

[Edited 2/3/13: The flavor of this soup was really good, but the texture was watery and chunky at the same time.  To be fair, I had to add 2 extra cups of water just to cover the 5 chopped zucchini I used, and I did blend it up AFTER adding the spinach to make it easier for Simran to eat (she didn't care for it).  I think in the future I'll either refrain from blending the spinach or add a can of white beans or lentils to make it a smoother consistency.  I'm sure Simran would prefer the latter.]