You know how I get all excited when a recipe turns out to be way more delicious than the ingredients suggest?  That happened.

It happend when nothing more than 2 lbs of sweet potatoes, a shallot, a little butter, and water for crying out loud, came together.  You’d think, and I thought, it would taste like potato water but NO, it’s so good I have made it twice in the last two weeks and eaten it for lunch and dinner over several days. I’m eating it now in fact!

And you know how I hate things that are called “healthy” but love when things just happen to be healthy?  Again with this soup.

CI says that what sets this recipe apart is that the ingredients are so minimal and allow the sweet potato flavor to come through.  I think they’re on to something.  And all it asks of you to to saute a shallot and thyme in some butter, add water, then sliced sweet potatoes, (which you basically steep in the water), add a tiny bit of brown sugar and cider vingear, then puree.  As with most soups it gets better over time.  I did find it needed a lot of salt (and that’s after using salted butter to saute) at the end and probably an extra teaspoon of vinegar but in my experience most CI recipes need salt.

Of course it wouldn’t be a Cook’s Illustrated recipe if they didn’t ask you to do something slightly nutty and and in this case it is adding some of the potato peel to the soup (for “extra earthiness”).  I’m just grateful they didn’t want me to juice the potatoes or put them through the dreaded food mill or brine them or something else that would have made me whine.

I topped with a little more thyme instead of the chopped chives recommended and you could also swirl in sour cream or creme fraiche if you’re fancy like that.  (P.s. it was only after writing this post that I discovered that CI had several topping recipes to accompany this soup.  And don’t they all sound swell?:  Buttery Rye Croutons, Candied Bacon, Maple Sour Cream and Sauteed Mushrooms).

And now, a giant leap for KCTB: a super pro recipe plug in with a functioning “print” option!!!  I’m so big time!


Sweet Potato Soup (from Cook's Illustrated, November/December 2015)

Prep Time: 10 minutes

Cook Time: 35 minutes

Yield: 4 servings

Sweet Potato Soup (from Cook's Illustrated, November/December 2015)


  • 4 tablespoons unsalted butter
  • 1 shallot, sliced thin
  • 4 sprigs fresh thyme
  • 4-1/4 cups water
  • 2 pounds sweet potatoes, peeled, halved lengthwise, and sliced 1/4 inch thick, 1/4 of peels reserved
  • 1 tablespoon packed brown sugar
  • 1/2 teaspoon cider vinegar
  • Salt and pepper
  • Minced fresh chives


  1. Melt butter in large saucepan over medium­ low heat. Add shallot and thyme and cook until shallot is softened but not browned, about 5 minutes. Add water, increase heat to high, and bring to simmer. Remove pot from heat, add sweet potatoes and reserved peels, and let stand uncovered for 20 minutes.
  2. Add sugar, vinegar, 1 1/2 teaspoons salt, and 1/4 teaspoon pepper. Bring to simmer over high heat. Reduce heat to medium­low, cover, and cook until potatoes are very soft, about 10 minutes.
  3. Discard thyme sprigs. Working in batches, process soup in blender (or with an immersion blender) until smooth, 45 to 60 seconds. Return soup to clean pot. Bring to simmer over medium heat, adjusting consistency if desired. Season with salt and pepper to taste. Serve, topping each with a sprinkle of chives.

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