Mix cake flour, soybean flour, sugar, and baking powder in a bowl until evenly combined.

Combine soy milk, canola oil, and vinegar in another bowl and mix with a fork until the oil droplets are well dispersed.

Pour the liquid mixture into the center of the dry ingredients and mix using a spatula until the dry ingredients are mostly incorporated.

Fold the dough several times to create layers and shape it into a cohesive mass.

Divide the dough using a scraper and place the portions onto a baking tray.