Japanese Sweet Potato Gelato (for Ninja Creami)

I decided to take the inside of roasted sweet potato, mix it up with gelato ingredients plus a splash of rum, and presto! This Japanese sweet potato gelato was born.

From the very first bite, I’ve been addicted to Japanese sweet potato, also called satsumaimo.

There are so many confections from Japan that use Japanese sweet potato because of its gentle, chestnut-like flavor, including everything from cakes to cookies to puddings and then some. My favorite Japanese sweet potato dessert by far, however, is a baked treat that is literally just called “sweet potato.”

Sorry, I know it’s confusing, but there is a dessert in Japan called “sweet potato” that is made out of the plant which is called “sweet potato” in English. To avoid too much confusion, I’m going to refer to the dessert as “suiitopoteto,” which is the Japanese pronunciation, and the tuber itself as “sweet potato.”

These are suiitopoteto I made using this recipe if you'd like to try making them. 
They're better when they're browned on top, but I got impatient. 

To make suiitopoteto, Japanese sweet potato gets mashed with a bit of sugar, butter, and sometimes other flavorings (rum is my favorite). Then, that delicious mash gets formed into small, oblong shapes; topped with egg wash; sprinkled with black sesame seeds; and baked. It’s such a perfect food, and I knew I needed to turn it into a frozen dessert. Suiitopoteto gelato sounded perfect.

You can’t use just any old sweet potato to make suiitopoteto, though, and this gelato is just as picky. You’ll need Japanese sweet potato to get the right flavor. I believe it is the same thing as Korean sweet potato. It has pinkish-purplish-brownish skin on the outside and whitish flesh on the inside that turns yellow once cooked. You can also use what’s labeled “boniato” at the store—it’s still unclear to me if it’s the same exact thing as Japanese sweet potato or if it’s just a very similar plant—because it has the same flavor, aroma, and appearance.

In any case, look for Japanese sweet potato/Korean sweet potato/satsumaimo first, then boniato as a backup, and lastly any other sweet potato that isn’t the one that’s bright orange and stringy on the inside. That one wouldn’t be bad, but its deeper, more caramel-like flavor isn’t what suiitopoteto tastes like.

When I set out to make suiitopoteto gelato, the first thing I tried was blending suiitopoteto itself into milk and sugar. The flavor was great, but unfortunately, due to the butter in suiitopoteto, it had that gritty texture that happens sometimes in the Ninja Creami when butterfat gets too agitated and makes butter. I knew I had to think of a different way—a way that didn’t use butter.

Then I thought of yakiimo, which is just roasted Japanese sweet potato. “Yaki imo” literally means grilled/baked potato. Simple. One ingredient. No possibility of buttering. I took the inside of roasted sweet potato, mixed it up with gelato ingredients plus a splash of rum, and presto! This Japanese sweet potato gelato was born.

Suiitopoteto has black sesame seeds on top, so I wanted to add some as a mix-in. Despite how pretty it looked, I actually preferred the gelato without them. They just got in the way and tricked my brain into thinking I was eating big ice crystals even though I wasn’t. Sometimes, simpler is better.

Anyways, I hope you all give this really beautiful and underrated flavor a try.

Japanese Sweet Potato Gelato Recipe

Ingredients

·       118 g (about ½ cup) yakiimo/cooked Japanese sweet potato, skins removed (instructions included in step 1)

·       ¼ teaspoon (1.54 g) salt

·       ½ teaspoon (2.46 g) dark rum

·       70 g (1/3 cup) sugar

·       250 g (1 cup) milk

·       70 g (scant 1/3 cup) cream

Directions

1.       Follow these instructions from Just One Cookbook to make yakiimo. TL;DR: Poke the sweet potatoes with a fork a few times, then bake them on a tray in a 325 F (163 C) oven for 90 minutes. Set the yakiimo aside and let it cool.

2.       Once cool enough to handle, scrape out the insides of the yakiimo using a spoon. You only need 118 grams, so feel free to snack on the rest. It’s delicious by itself!

3.       Mash the yakiimo using a fork, making it as smooth as possible, before mixing in all of the other ingredients one at a time. You can also just blend everything until smooth if that’s your preference. I prefer mixing in the cream by hand to avoid buttering.

4.       Pour the gelato mixture into a clean, empty Creami pint and freeze overnight or until completely frozen. Once solid, churn it using the Ice Cream setting on the Ninja Creami. Respin as needed to make a smooth and creamy gelato. Enjoy your Japanese sweet potato gelato!

Q and A

Q: Can I omit the rum?

A: The very small amount of rum adds a fantastic depth of flavor, and while you could omit it if absolutely necessary, I must strongly recommend against skipping it. I also don’t recommend adding more or else it becomes overpowering. If you can have alcohol, please use the exact amount of rum this recipe calls for.

Q: What kinds of sweet potatoes can I substitute for Japanese sweet potato?

A: Korean sweet potato and boniato are perfect substitutes. You could also use ube or another purple-fleshed sweet potato if you like the color and taste. As a very last resort, you can use a normal sweet potato.

Q: Can I make this with less sugar or a sugar substitute?

A: Without sugar, frozen desserts freeze harder. If something freezes too hard, then you need to use the Lite Ice Cream setting on the Ninja Creami, which presumably churns more vigorously. When it churns harder, you run the risk of cream turning into butter and creating an unpleasant texture. In other words, if you need to use the Lite Ice Cream setting, the texture might not turn out right.

Q: What should I serve with Japanese sweet potato gelato?

A: This recipe for corn ice cream would be beautiful with it. Both flavors are subtly sweet and buttery. Red bean would be a great pairing, too, if you’d like to pair it with another Japanese flavor. You can also sprinkle black sesame seeds on top if it strikes your fancy.