Purple: The New Orange

First, I must admit that today's recipe is an experiment.  It is not so much an experiment in taste as it is an experiment in color.  And it is one that may not work.  I say that now, as I write this post and the 'experiment' cooks.  The deciding factor will be the final photo.

I was in the 17th Street Market the other day.  For non-Tucsonans, this is a wonderful warehouse-style market with aisles and aisles of imported foods from around the world, and the largest walk-in vegetable cooler I have ever seen.  While looking for celery root, I spied some sweet potatoes.  And it is from these sweet particular potatoes that I titled today's post.  They are purple and not orange - although, having tasted them before, they taste very similar to their orange and yellow-fleshed siblings.

Seeing them took me back to a meal Mark and I shared in the prow of The Wanamaker, a tugboat-cum-restaurant that was moored on the Piscataqua River in Portsmouth, New Hampshire.  The food at The Wanamaker was excellent in its early days and dining there made for a special experience for out-of-town guests - an opportunity to eat atop a tugboat in the harbor while the offshore breezes cooled the afternoons.   But, on biting cold winter nights or hot sultry summer evenings, we dined inside, "down under," to be warm or cool, respectively.  The interior was beautiful, paneled in mahogany with polished brass railings and hardware.  In the middle of the room were glass windows to view the working parts of the engine.  A few portholes graced the walls and, if you stood on your tippytoes, you were eye-to-eye with the undulating waves of the river.

Back to the meal. We both ordered a sweet potato vichyssoise.  While not technically a vichyssoise (this was simply a hot sweet potato soup), it was good and it inspired me to make a sweet potato vichyssoise.  I have made several versions over the years, sometimes with ginger and spices while at other times I added chipotle chiles for smokiness and a bite.  But, when I saw the purple sweet potatoes, all I could think was how beautiful lumps of crab would look mounded in a pool of rich purple soup. At least I hoped it will be purple. Right now, it looks like murky dishwater.  So, dear readers, are you ready?

Voila! It came out looking quite beautiful, although not exactly as I had imagined it.  It was more lavender than purple, which suits me fine, and the flavor is wonderful - sweet and smooth.  Purple sweet potatoes may be hard to find but, really, any variety will do. No matter what kind of sweet potato you use to make it, it will be good, and can be served cold or hot, depending on the weather, and with or without the crab.

Oh ... a note on sweet potatoes and yams from Mark, my resident food historian. Sweet potatoes are native to South America and yams to Africa. And, unless you have an amazing market that imports vegetables from Africa, you have probably never seen a yam no matter how many times the supermarket tells you that you have. The confusion of the unrelated Old World and New World tubers probably began when enslaved Africans transferred their word 'yam' (nyami) to the American root.  This usage went national in the 1950s when the Louisiana legislature promoted the newly-introduced orange sweet potato under the word 'yam.'  It is also interesting that neither yam nor sweet potato is related to white (red-skinned or blue) potatoes. And, just an FYI, a yam is generally 1-2 feet long, and can grow as large as 6 feet.

So, as the weather gets warm in Tucson and remains cold elsewhere, this soup will work all climates!

- David

Sweet Potato Vichyssoise

8 tablespoons butter, divided
4 leeks, white and light green parts only, cleaned and sliced
1 large sweet onion, chopped
1/4 to 1/2 teaspoon cayenne pepper
1 pound sweet potatoes, peeled and thinly sliced
1/2 pound russet potatoes, peeled and thinly sliced
6 cups chicken broth
2 cups water
1 teaspoon salt
freshly ground pepper
1 cup heave cream
1/2 pound fresh crab meat
1/2 teaspoon paprika

Melt 7 tablespoons butter in a large soup kettle. Add leeks and onions and cook over medium-low heat until soft, being careful not to brown them.  Add cayenne pepper and stir to incorporate evenly.  Add the potatoes, broth and water.  Bring to a boil and then reduce to simmer.   Cook the soup for 20-25 minutes, or until potatoes are soft.  Season with salt and pepper.  Purée in a blender in batches and pour into a large bowl through a fine mesh sieve.  Stir in cream and chill.  (If serving hot, reheat after adding cream.)  Before serving, melt remaining tablespoon butter and sauté crab briefly with paprika.  Serve soup in shallow bowls with about 1 ounce of crab meat mounted in the center of each plate.   Serves 8.


  1. David,
    That looks and sounds great! I'll have to head down to 17th St to see if they still have any of those purple sweet potatoes. Thanks for sharing!

  2. Thanks, Kevin. They were in amongst the indecipherable Asian greens...

  3. Absolutely beautiful!

    Enjoyed the yam-sweet potato review, too....I know that we just discussed that subject (over a marvelous dinner of lamb ragoût and that wonderful polenta made from that white cornmeal you wrote about in an earlier issue), but my mind is a sieve: what, then, are the tubers that we find in our grocers in the "yam" bin?

    Many thanks,

  4. Susan,
    Thanks for your comment! I think we only discussed the title for this post, leaving the actual ingredient a secret. But, then again, we might have taled about it - my mind is a colander (bigger holes) so much more seeps out. As for the yams you see in the store, Mark will answer in more detail but suffice it to say... they are sweet potatoes!


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