To read more about this soup, see Deborah’s account of making it for a crowd.

Steps

1. First, fill a blender jar with the chunks of cucumber. Then pour in the quart of yogurt. Whirl away until green and smooth. Pour most of it in a bowl and set aside.
2. Add the herbs to what’s left in the blender jar. Also pour in the olive oil and a scant teaspoon of salt. Purée until flecked with green, then add it to the rest of the soup.
3. Stir in the finely grated zest of two lemons and the juice of one. Taste for salt and lemon, adding more of each if needed. Refrigerate, preferably overnight so the flavors can build.
4. Bring the water to a boil and cook the quinoa. Then, while it’s warm, toss it with a little olive oil and season it with salt, pepper, and remaining lemon zest. Let it cool.
5. To serve soup, ladle it into cups or bowls, adding a tablespoon or two of quinoa to each serving. Drizzle a few drops of olive oil over the surface, and there you are.