Prep time: 25 minutes plus 3 hours chill time
Cook time: 36 minutes
A potato in the mix helps create a thick, silky soup. Make sure to use yellow zucchini, not yellow summer squash; it has a more vibrant color. If you choose to make this vegetarian, use a light-colored rather than a darker vegetable broth, or the soup will look muddy; or use water.
The soup needs to be refrigerated for at least 3 hours before serving.
From Debbie Amster, a holistic health coach, cooking teacher and healthful-foods caterer based in Olney, Md.
6 thin leeks, chopped (1 pound; about 5 cups)
2 tablespoons olive oil or butter
1 pound yellow zucchini, sliced (about 3 cups; see note)
1 medium white boiling potato, coarsely chopped (about 1 1/2 cups)
No-salt-added vegetable or chicken broth or water (about 4 cups; see note)
Freshly ground black pepper
Chopped dill, for garnish
Fill a bowl with cold water and add the chopped leeks; soak them briefly to dislodge any grit. Use a strainer to scoop the leeks out of the water, and use paper towels to pat them dry.
Heat the oil or butter in a soup pot over medium-high heat. Add the leeks and a pinch of salt; cook until the leeks have softened, about 6 minutes. Add the zucchini and potato, then add enough broth to just cover the vegetables. Bring to a boil over medium-high heat, then reduce the heat, cover and cook for 20 to 30 minutes, until the vegetables are tender, adjusting the heat so that the liquid is barely bubbling at the edges.
Use an immersion (stick) blender and blend to a thick puree. (Alternatively, if you use a regular blender, transfer in batches; remove the center knob from the lid and cover the opening with a towel to contain splash-ups.) Season with salt and pepper to taste.
Allow the soup to cool, then transfer to a storage container and refrigerate until chilled, at least 3 hours.
When ready to serve, garnish with sprigs of dill.
Per 1-cup serving (using olive oil and vegetable broth): 110 calories, 2 g protein, 17 g carbohydrates, 4 g fat, 1 g saturated fat, 0 mg cholesterol, 180 mg sodium, 2 g dietary fiber, 5 g sugar