aka goguma cake (고구마케이크) in Korean. It is a well known cake in Korean cake shops because it utilizes those delicious Korean sweet potatoes that are sweet, soft, and fluffy. This is a fluffy layered cake (from a Genoise sponge cake) that has a creamy sweet potato filling (made from Korean sweet potatoes) and a light whipped cream.
How are Korean sweet potatoes different from regular sweet potatoes?
Korean sweet potatoes have a red purple skin and yellow flesh on the inside, while regular sweet potatoes have an orange flesh. Japanese sweet potatoes are also very similar to Korean sweet potatoes. They’re both sweeter than regular sweet potatoes which makes them so satisfying. I love roasting them for a nice snack. It becomes soft and caramelized on the inside with a crispy skin.
You can use Japanese sweet potatoes for this recipe, it works the same. They can both be found in Asian grocery stores.
This cake uses a Genoise sponge cake base (recipe here). The cake is soft and fluffy and makes this cake so so good. You can make the cake ahead of time (or even a day ahead). Just remember to wrap it tightly in plastic wrap after it has cooled, in order to retain the moisture and fluffiness of the cake.
One more picture – just because I worked so hard on making and decorating it!
If you do try out this recipe, be sure to leave a comment and/or give it a rating! I’d also love to see your creations so don’t forget to tag me on Instagram!
Korean Style Sweet Potato Cake
Ingredients
Sweet Potato Filling
- 500 g Korean or Japanese sweet potatoes (the ones with yellow filling and purple skin)
- ½ cup whipping cream (or heavy cream)
- ½ cup milk
- 2 tbsp sugar
- 2 tbsp unsalted butter
Whipped Cream
- 1 cup whipping cream
- 1½ tbsp sugar
Syrup
- 1 tbsp sugar
- 2 tbsp hot water
Toppings
- Finely chopped pistachios (optional)
Instructions
Sweet Potato Filling
- Boil the sweet potatoes in a pot of water until they are soft and completely cooked through.
- Peel and mash the sweet potatoes while they’re hot.
- In a medium saucepan, add in the rest of the ingredients. Mix and cook until the butter has melted. Then mix in the mashed sweet potato until creamy.
- To make it extra creamy and delicious: I always blend the mixture with an immersion hand blender. You can also blend it in a regular blender or run it through a sieve. Cool the filling completely.
Whipped Cream
- In a large mixing bowl, beat the cream with the sugar with an electric hand held mixer until it’s up to 70% (which means medium peaks – soft, but still holds a form). Set aside.
Syrup
- Mix the ingredients together in a small bowl. Set aside.
Assembling
- Slice the genoise sponge cake in 3 even layers.
- Brush some of the syrup on top of two of the cakes (this helps the cake to stay soft and moist even after you put it in the fridge!)
- Spread the sweet potato filling on 1 sliced cake, and top with the second layer of cake. Repeat steps 2 and 3 again for the second and third layer.
- Spread the whipped cream all over the cake.
- Decorate it however you like! I had extra sweet potato filling leftover, so I just piped it on top along with the whipped cream. Top with finely chopped pistachios (optional). Slice, serve, and enjoy!
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