Cold Zucchini Soup from Union Square Cafe

It started so innocently.  We were in New York on a hot summer day and thought we'd try to get in the Union Square Cafe for lunch. We wanted something light; soup and salad with some of their wonderful bread.  After a few tastes, we looked at each other and I said, "This is perfection."  Perfectly light but flavorful cold zucchini soup and a simple salad perfectly dressed with a perfect vinaigrette rounded out by delicious bread and fresh cream butter.  One of the better meals I've had in a restaurant in recent memory. It may sound strange to order just soup and salad at one of the more notable New York restaurants, but it was just right at the right time.  I tracked down the vinaigrette made with grapeseed oil but had to tackle the zucchini soup as best I could.  I'm not a big zucchini fan but I'm obsessed with this soup.  It's so simple and doesn't take long to make. The basil is my idea.
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2 tbls olive oil
3 cups grated zucchini, about 3 medium.
1 cup diced sweet onion
1/8 tsp crushed red pepper flakes
1 tsp Kosher salt
1/2 tsp fresh ground pepper
1 cup fresh packed basil leaves
2 cups chicken stock (homemade preferred)
1/4 cup heavy cream

Heat the oil over medium heat until shimmering.  Add the zucchini, onion and crushed red pepper flakes.  Add the salt and pepper and cook until vegetables are soft but not browned and the vegetables  have released their liquid. Take off heat and let cool for 15 minutes.  Transfer to a high speed blender or food processor and add basil and chicken stock.  Blend until smooth. Taste and adjust seasoning, add cream and blend. Chill throughly, 6 hours or over night. Garnish with fresh basil or coutons.