Step 1Spray a 5-quart saucepot with the nonstick cooking spray. Add the olive oil and heat over medium heat until hot. Stir in the onion and cook, stirring, until tender, about 2 minutes. Add the garlic and cook an additional minute, stirring. Add the zucchini and cook 2 minutes, stirring.
Step 2Stir in the vegetable broth and the water and bring to a simmer. Reduce the heat to medium-low, cover and simmer until the zucchini is quite tender, about 15 minutes.
Step 3Puree the soup mixture in a blender. Add the cream and blend again. Add the salt, blend and adjust seasoning if needed.