Prepare the kuromame by soaking for 4-6 hours and boiling them.
Make the cake batter by mixing the fresh okara with the matcha until it's evenly distributed.
Separate the egg whites and yolks. Mix the egg yolks with 1/2 of the kuromitsu and soy milk. Whip the egg whites until soft peaks form, then add the rest of the sugar and continue to whip until stiff peaks form.
Mix the egg yolk mixture into the okara mixture in 2 batches, add the black soy beans and stir in until evenly distributed.
Add the whipped egg whites to the okara mixture in 2 batches, folding gently after each addition. Pour the mixture into the rice cooker pot and drop the pot from a height onto a surface to eliminate excess air bubbles.
Cook in the rice cooker. Do this by first leaving the cake to cook on the normal rice cooking mode until it's half-baked. Then set it to cook again on quick cooking mode.
To cool the cake, switch off the warming function, then open the lid and allow it to cool inside the rice cooker.
Let the cake thoroughly cool until you can easily remove it from the rice cooker pot, then it's ready to eat.
Here is another variation to this recipe: Mix used green tea leaves into the batter in place of the black soy beans, then sandwich some koshi-an and brown sugar walnuts for an authentic Japanese confectionary.
For this version, the egg yolk should be mixed with 1 tablespoon of kuromitsu and the egg white should be mixed with 1 tablespoon of condensed milk. The cake should contain 100 g of koshi-an and 3 brown sugar walnuts. One cake is 145 kcal.
Story Behind this Recipe
Everyone's talking about black soy beans and okara since they're good for dieting?! I came up with this recipe by referring to a recipe made by a friend who makes cakes made of okara.
This cake is low in sugar. If you want to make it sweeter, increase the amount of kuromitsu to 2-3 tablespoons. There is a version of this recipe that uses pancake mix. Recipe ID: 1132630.