Mix flour in water well without any lumps. Cook over medium-low heat, stirring consistently with a wooden spoon, whisk or spatula to prevent burning and sticking while you cook along the way.

The mixture becomes thicker and thicker. Once you notice some “lines” appear in the mixture for every stir you make with the spoon. It’s done. You get the tangzhong. Remove from heat.

Transfer into a clean bowl. Cover with a cling wrap sticking onto the surface of tangzhong to prevent from drying up. Let cool. Chill in fridge for several hours or overnight. Then the tangzhong is ready to be used. (Note: When you are ready to use the tangzhong, just measure out the amount you need and let it rest in room temperature for a while before adding into other ingredients. The tangzhong can be stored up to a few days as long as it doesn’t turn grey. If so, you need to discard and cook some more.)