3 ways to serve Hawaiian sweet potatoes

A few weeks ago, I cooked with purple-fleshed sweet potatoes for the first time. I’ve tasted them here and there, usually in Hawaii, where they are called Hawaiian sweet potatoes, though their official name is Okinawan sweet potatoes, mirroring their popularity there.

I baked one and ate it simply, with a bit of butter, salt and pepper. Honestly, it was one of the most delicious things I’ve ever eaten.

These sweet potatoes have tan-colored skin and are typically labeled as purple sweet potatoes. They are less sweet than the sweet potatoes, including those labeled (incorrectly) as yams, in our supermarkets. They are readily available in most Asian markets, including Asia Mart at 2481 Guerneville Road in Santa Rosa.

When buying these sweet potatoes, know that they vary greatly in size. In baking, the smaller, longer ones will be done before the bigger, fatter ones. When cooking them on the stove, cut them into similar sizes so they cook evenly.

When it comes to nutrition, these sweet potatoes are very attractive. They are not related to potatoes and are not part of the nightshade genus, which people with certain medical conditions, including arthritis, are encouraged to avoid. They are a member of the Ipomoea genus, which includes morning glories.

One hundred grams (about 3 ½ ounces) contain 140 calories, 27 grams of carbohydrates and a gram of protein. Vitamins and trace minerals include vitamins C and A, calcium, iron and potassium. They are packed with compounds known as anthocyanins, responsible for their deep purple hue, which are powerful antioxidants.

These baked sweet potatoes couldn’t be simpler or more delicious. If you have a toaster oven, you can use it to avoid heating a large oven. And you can, if you like, omit the butter. The baked sweet potatoes are delicious on their own, neat.

Baked Okinawan Sweet Potatoes with Ginger Garlic Butter

Makes 4 servings

4 small-medium Okinawan sweet potatoes, washed

½ cup (1 stick) butter, at room temperature

3 plump garlic cloves, crushed and minced

1 tablespoon grated fresh ginger

½ teaspoon ground white pepper

Kosher salt

Black pepper in a mill

Preheat the oven to 375 degrees. When it is heated, set the sweet potatoes directly on the rack and cook until tender, about 30 to 45 minutes, depending on their shape and size. To test for doneness, quickly squeeze each one; there should be plenty of give. If you aren’t sure, insert a toothpick or bamboo skewer into the fattest part of one of the sweet potato; if it goes in easily, it is done.

While the sweet potatoes cook, make the flavored butter. Put the butter into a small bowl; add the garlic, ginger and white pepper; and use a fork to mix thoroughly. (You can also do this in a small food processor.) Cover and refrigerate until ready to use.

To serve, break open each sweet potato, set on plates and pass the butter, salt and pepper.

Coconut milk resonates beautifully with these sweet potatoes, expanding what we perceive as tropical flavors. If you keep Hawaiian Chile Water on hand, try a shake or two with this dish; the little burst of heat is quite delicious.

Mashed Okinawan Sweet Potatoes

Makes 6 to 8 Servings

2 pounds (6 medium) Okinawan sweet potatoes

Kosher salt

⅓ cup coconut milk, plus more as needed

Black pepper in a mill

½ cup shelled pecans, lightly toasted

Hawaiian Chile Water, optional

Use a vegetable peeler to peel the sweet potatoes and cut them into chunks of fairly equal size. Put them in a saucepan, add water to cover by about 1 inch, add a generous teaspoon of salt and bring to a boil over high heat. Reduce the heat to medium-low and simmer until the sweet potatoes are tender, about 9 to 14 minutes, depending on the size of the chunks.

Drain the potatoes. If you like, pour the water into a bowl or large cup and save it for making soup. If not, discard it. Set the pan back on the heat and evaporate any water that lingers.

Mash the potatoes with a fork or a small potato masher. Add the coconut milk and several turns of black pepper and mix until smooth. If the mixture seems a bit dry, add more coconut milk, a tablespoon at a time, until you reach the desired consistency.

Taste, season with salt if needed and turn into a serving bowl. Scatter the pecans on top and enjoy right away, passing the chile water alongside.

A few local farmers offer fresh soy beans at farmers markets, but you also can find them at any market with a sushi stand. They are also available frozen. When I don’t have fresh, I get frozen ones at Santa Rosa’s Asia Mart.

Okinawan Sweet Potato Salad with Cucumber Vinaigrette

Makes 6 to 8 servings

Cucumber Vinaigrette (recipe follows)

2 pounds (about 6) Okinawan sweet potatoes

Kosher salt

2 celery stalks, trimmed and cut into thin diagonal slices

5 green onions, trimmed and cut into thin rounds

1 small (about 5 inches) Armenian cucumber, cut into thin half rounds

½ cup cooked and shelled edamame, optional

Make the vinaigrette.

Peel the sweet potatoes, cut them into ¼-inch-thick rounds and put them into a medium saucepan. Cover with water by about an inch, add a generous teaspoon of salt and bring to a boil over high heat. Cook until just tender, about 8 to 10 minutes. Drain, saving the cooking liquid for soup if you like, and return to medium heat briefly to evaporate any water that lingers on the sweet potatoes.

Put the cooked and drained sweet potatoes into a wide, shallow bowl and add the celery, green onions, cucumber and edamame. Toss very gently, pour half the dressing over the salad, cover and let rest for 15 minutes or so.

To serve, pour the remaining vinaigrette over the salad and enjoy at room temperature.

Cucumber Vinaigrette

Makes about ½ cup

1 teaspoon minced red onion

¼ cup cucumber juice (see Note below)

1 tablespoon freshly squeezed lemon juice, plus more to taste

Kosher salt

1 teaspoon snipped fresh chives

8 to 10 spearmint leaves, very thinly sliced

3 tablespoons peanut oil, plus more to taste

Put the onion into a small bowl, add the cucumber juice and lemon juice and set aside for a few minutes.

Season with a few pinches of salt, add the chives and mint and pour in the oil. Stir and taste for salt and acid balance, adding a bit more lemon juice if it is a bit flabby or more oil if it is too tart. Cover and refrigerate until ready to use.

Note: To make cucumber juice, peel and mince a slicing cucumber (not a pickling cucumber). Put it in a colander or strainer, stir in ½ teaspoon kosher salt and let drain for 30 minutes, stirring every now and then.

Michele Anna Jordan is the author of 24 books to date, including “Vinaigrettes and Other Dressings.” Email her at

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