- 1 tablespoon unsalted butter
- 2 tablespoons extra-virgin olive oil
- 1 small onion, finely chopped
- 1 garlic clove, thinly sliced
- Kosher salt
- Freshly ground pepper
- 1 1/2 pounds zucchini, halved lengthwise and sliced 1/4 inch thick
- 2/3 cup vegetable stock or low-sodium broth
- Julienned raw zucchini, for garnish
- In a large saucepan, melt the butter in the olive oil. Add the onion and garlic, season with salt and pepper and cook over moderately low heat, stirring frequently, until softened, 7 to 8 minutes. Add the zucchini and cook, stirring frequently, until softened, about 10 minutes. Add the stock and 1 1/2 cups of water and bring to a simmer; cook until the zucchini is very soft, about 10 minutes.
- Working in 2 batches, puree the soup in a blender until it's silky-smooth. Return the soup to the saucepan and season with salt and pepper. Serve it either hot or chilled, garnished with julienned zucchini.
The soup can be refrigerated overnight.