My introduction to the Japanese sweet potato (satsuma- imo) occurred accidentally, when I brought home a bag of dusty pinkish skinned sweet potatoes from the market. After scrubbing and simmering the tubers until tender, I cut one open and was startled to discover that its flesh was a pale yellow-ivory color, when I was expecting a bright orange interior. If the color was a surprise, its flavor was even more of a revelation. Less sweet than a standard sweet potato, the Japanese tuber is slightly firmer and dryer, and has a subtle delicious chestnut flavor. Since that fortuitous discovery, the Japanese sweet potato has become a staple in my pantry and the basis for many quick nutritious meals and snacks.
To prepare, scrub sweet potatoes in warm water, rinse, and place in one layer in a soup pot. Add enough fresh water to almost cover the potatoes. Place lid on pot and bring to a boil; lower heat and simmer gently until tender but not mushy, which may take about 45 minutes depending on the size of the potatoes. When done, remove from pot and cool a bit before serving (or sampling!) to allow the natural sugars in the potatoes to develop. Cooked sweet potatoes store well for up to a week in the fridge and make great portable instant snacks.
There are infinite ways to serve Japanese sweet potatoes, but their natural deliciousness requires little additional preparation. For a quick meal, steam or stir fry your favorite leafy greens. Slice a few cooked potatoes into rounds or chunks ( the skins will come off as you cut them) and serve on a bed of warm greens; season with a little tamari sauce to taste.