This recipe doesn't use flour, butter, or sugar. You can make this simply by mixing the ingredients and then microwaving. Fluffy and moist like castella sponge cakes.
I was craving for castella cakes, so here's my try on making it with 100% okara.
Make sure to mix the ingredients well. It's easier if you use 2 pairs of chopsticks (4 chopsticks) to stir.
Enjoy Japanese food around the world.