Mix ingredients: In a bowl, combine the soymilk, chickpea flour, shio koji, sugar, apple cider vinegar, olive oil, mustard, and baking soda. Whisk until completely smooth.
100 g plain soy milk, 30 g chickpea flour, 1 teaspoon shio koji, 1 teaspoon cane sugar, ½ teaspoon apple cider vinegar, 10 g olive oil, 3 g mustard, 2 pinch baking soda