Put the bowl on a scale, and measure in the flour, Chinese apricot kernel flour, katakuriko, and baking powder. Stir with a whisk (as an alternative to sifting the ingredients), add the sugar and salt, and mix again.
Add the soy milk (or milk), then briskly stir without beating the batter. (A few lumps are okay.)
Fill aluminum cups with the batter, arrange in a steamer, and steam for 8-10 minutes over high heat. They will turn out better if you leave extra space in the steamer without overcrowding it.
This is the Chinese apricot kernel flour I used.
Here is the plain version.
It's also tasty with raisins.
Story Behind this Recipe
I wanted to make sweets using Chinese apricot kernel flour other than almond jelly. To enhance the sponginess, I used katakuriko and soy milk, but it is also tasty with just flour (increased to 100 g), and using regular milk. These are low in sugar, since almond powder is sweet.
Steam must rise from the steamer or else the buns won't turn out fluffy. The buns puff up in aluminum cups more nicely than in paper or silicon cups. It's best not to fill the baking cups too much with batter. I recommend filling them about 70%.