Prepare a pan with water, oil, or any flours remaining on its surface. Line just the bottom with kitchen parchment paper.
Preheat the oven to 180°C.
In a bowl, mix together the egg yolk and the kuromitsu.
Add the rice flour and mix. You don't need to sift the flour.
Put the sugar and egg whites into a separate bowl. Whip until stiff peaks form.
Divide the mixture from Step 5 into three portions, mixing one portion at a time into the mixture from Step 4.
Pour the batter into the pan. Drop the pan onto a table a few times to shake out the larger air bubbles.
Bake in the oven for 10 minutes at 180°C, then lower to 160°C and bake for 20 minutes more. If a skewer or toothpick inserted through the center comes out clean, it is done.
Open the oven door and let the cake cool in the oven.
It's like a pound cake, but it will deflate and flatten a bit. Once cooled, loosen the edges with a knife and remove from the pan.
If you wrap with plastic wrap or foil and let it sit, the cake will become moist and the flavors will settle in more.
Cut off both of the ends to make it look like a castella cake. It's such a cute mini-sized cake!
Story Behind this Recipe
I wanted to find a way to make delicious treats using 100% rice flour. With this recipe, you'll be able to prepare delicious cake you'll want to make again and again.
If you wrap the cake tightly with plastic wrap or aluminum foil, the cake will turn out very delicious the next day. If you let it chill in the refrigerator for about 15 minutes, it will be a lot easier to cut cleanly. Here, I used riz farine for baking.