Chilled avocado and cucumber soup

Avocado and cucumbers blend with yogurt to make a creamy summer soup.

This post was written by Marion Boyd.

Hot, hot, hot, hot, hot, hot, hot, hot, hot, hot. Dry. Hot. Right now in Chicago is a breezy, refreshing 98 degrees F. We are crawling around on the surface of the planet like miserable bugs.

As Terry has sometimes mentioned, I used to address weather like this by making cold cucumber soup. The trigger for this was the legendary cold cucumber bisque we would have at the former Balaban’s in St. Louis. My versions varied tremendously, and they were always interesting, but they were never like Balaban’s. That recipe was a closely guarded secret – one of those instances when everyone who worked there would get all coy and diffident if you asked about the ingredients. “Oh, I don’t know, some people think it has summer savory in it,” they would say in a demure tone. “I’ve heard it might have yogurt in it.” Sometimes they would turn it into a question: “Sour cream?” 

Like most people, I prefer getting a straight answer, even if the answer is “I’m not allowed to tell you,” so the Balaban’s cucumber bisque experience also included a faint annoyance factor. But, mmmmmm, cold cucumber soup, so for years I kept trying and trying to duplicate it. In the process, I made a great variety of cucumber soups. Then I just kind of stopped making them at all.

But then came this summer. Farmer’s markets full of cukes, but the kitchen so miserable. For several weeks, I’ve been trying to make a no-cook cucumber soup. Some tasty things have come out of that, but not any that are souplike. They are more like refreshing savory smoothies. Delicious, but to my mind not a soup.

Over the weekend, Terry was out of town, and I embarked on a stubborn frenzy of experiments. To get that souplike consistency, I had to give up on no cooking. After a couple of misses, one near-hit involving mint and dill, and one really ghastly disaster, I got to this: A suave, mild chilly mix of cucumber and avocado, garnished with crisp little chunks of radish.

This soup starts out hot, with a little cooking, on top of the stove, and then some cool-down time in the fridge, and then some zipping around in the food processor. Don’t omit the radish garnish – the cold crunchiness is an essential part of this recipe. The dusting of sumac, with its lemony freshness, is also indispensable.

If you have been canceling your barbecue get-togethers due to the weather, try this for company. It would be a nice little starter for four, followed by a simple fish and a leafy salad, or a good part of lunch for two, with a light sandwich.

Cold Cucumber Avocado Soup with Radish Garnish
Four starter servings (or two greedy ones)

1 cup chicken stock
10 ounces Yukon Gold potatoes
10 ounces cucumber, peeled, seeded and chopped into chunks (see Kitchen Notes)
Flesh of one ripe avocado
1 tablespoon lime juice
1/2 cup buttermilk
1/2 cup Greek yogurt (or use 1 cup of buttermilk or Greek yogurt)
1/2 cup half and half
1/2 cup radish cut into 1/2-inch rounds, then into quarters and halves
powdered sumac

First, prepare the cucumber and radish, and put them in the refrigerator so they get nice and cold.

Peel the potato, rinse and dice it, and put it in a saucepan with the chicken stock. Cook until the potato is very soft. This will go faster if you cut the potato into small pieces. This ends the heating portion of your soup making.

Pour the potato and stock into a container and refrigerate until completely chilled.

To assemble, pour the potato and stock mixture into the bowl of a food processor. Add the lime juice, cucumber, avocado and the dairy products (give the buttermilk a good shake before measuring it). Add a dash of salt, then process until completely smooth, for at least 3 minutes.

If the soup seems too thick (too much like a dip, say), cautiously add a little icy water until the soup is the texture you prefer.

Ladle into chilled soup plates or bowls that complement the elegant pale green color. Then add the radish garnish and, finally, sprinkle a pinch of powdered sumac over each bowl and serve.

Kitchen Notes

To peel or not to peel. If you use unwaxed cucumbers, you can leave about half the peel on, which will contribute to the pretty color.

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