I love Japanese sweet potatoes (also called Japanese Yam). They are less watery compared to “American” sweet potatoes and sweeter in my opinion. My favorite way of eating them is baking. We called them yakiimo (焼き芋) in Japanese. When I was growing up in Japan, baked sweet potatoes were sold by a guy hauling a cart. There is an oven in a cart which bakes sweet potatoes. Stones are put in the oven to heat sweet potatoes. It’s kind of hard explain how it works but this stone-baked method makes sweet potatoes so much sweeter and tastier.
I did some research to recreate sweet potatoes baked with stones. They keys seem to be (1) sweet potatoes should be dry when they are baked and (2) they should be baked at a low temperature for a long time. I will share my method step by step. A short version of the recipe is also available at the bottom of this blog post.
- Wash sweet potatoes the night before and dry them thoroughly. Pick sweet potatoes with dark reddish skin color.
2. Preheat oven at 300 degrees F (150 degrees C). You can skip this. Sometimes I don’t preheat the oven.
3. Wrap sweet potatoes with dried paper towel then with aluminum foil. I use the shiny side inside. Paper towel will absorb moisture while basking and keeps sweet potatoes dried.
4. Place the foiled sweet potatoes on a baking sheet. The baking sheet transfers more heat and helps cooks faster (although this baking method takes a long time). I usually bake as many sweet potatoes which fit on a baking sheet (8 to 10 depending on the size).
5. Baked them until they become very soft. The longer you bake, the sweeter they become. With my electronic convection oven, it usually takes 2 1/2 to 3 hours. Yes, it takes that long! When I’m in a hurry, I bake them at a higher temperature (like 350 degrees F) but it tastes better when I bake them at 300 degrees F. Baked Japanese sweet potatoes should be golden inside and kind of fluffy. It takes a long time to bake them but you can forget about them once they are in the oven. I usually put them in the oven before I start cleaning my place and doing laundry. When I’m done with house chores, perfectly baked sweet potatoes are waiting for me 🙂
Baked sweet potatoes are stored well in the freezer. After they become completely cool, I usually wrap them in the aluminum foil that I bake them with and put them in a plastic bag to store in the freezer.
- Japanese sweet potatoes (yam) - as many as you like!
- Wash sweet potatoes the night before and dry them thoroughly.
- Preheat oven at 300 degrees F.
- Wrap sweet potatoes with dried paper towel then with aluminum foil.
- Place the foiled sweet potatoes on a baking sheet.
- Baked them until they become very soft.