Chilled Zucchini and Green Bean Soup with a Pesto Swirl

Found this in a newspaper a long time ago. Just found the torn out newspaper page in my laptop bag :P

2 T EVOO
1 small sweet onion, chopped
1 lb zucchini, ends trimmed and thinly sliced
4 c reduced-sodium chicken broth
10 oz package frozen shelled edamame
1/2 lb green beans, ends trimmed
1/2 t salt
1/4 t ground white pepper
1/4 c store-bought basil pesto
1/2 c reduced fat sou cream

In a large saucepan over medium-high, heat the oil. Add the onion and zucchini and saute until very soft, about 10 minutes.
Add the chicken broth and bring to a boil. Stir in edamame and green beans and simmer, uncovered about 20 minutes. Remove from the heat and cool for 15 minutes.
Transfer the soup in batches if necessary to a blender or food processor. Puree, then season with salt and pepper.
Serve soup chilled or at room temperature. When serving, divide the soup among 6 bowls and swirl a spoonful of pesto into each. Top with sour cream, if desired.