1) Heat oil in large pot over medium heat. Add garlic and onions, and cook for 3 - 4 min. until they are light golden brown.
2) Add zucchinis, broth and water. Bring to a boil, then cover and reduce heat to medium. optional: Scoop brown foal (scum) off surface every now and then.
3) Cook for 10-20 min. or until zucchini is very soft.
4) Use a stick blender to whizz until smooth.
5) Stir thru cream and milk. Add salt and pepper to taste.
6) Ladle into bowls, swirl over a touch of cream, if desired, a pinch of shredded parmesan and more pepper. Serve hot or room temperature.