Chilled Sorrel and Spinach Soup

Sleek and smooth, this tart soup starts a summer meal with style. The flavor is sprightly and springy, even if the dark olive color isn’t—but marbled with cream, the look is anything but drab. Chicken broth is the standard for soups of this kind, but I prefer a clear vegetable flavor. Most recipes recommend stripping sorrel stems, but I find that both cultivated and wild melt softly into the soup. This doubles neatly.