The buns were steamed over moderate heat. The filling inside the dough would burst out quickly when it was steamed over high heat. This was why using medium heat to steam was the best. Before that, she rested the buns for fifteen minutes before steaming.
The dough was made with yeast so the time was needed to allow for the fermentation process or proof several times at various preparation stages. When the dough had completed the fermentation steps, it's ready to be shaped into buns.
Lu Xinyi didn't wait for too long as the yeast would further expand the volume, and it would leave a gap between the dough and the filling. Eventually, the dough would rise too much and become out of shape after steaming.
Too much steam could cause wrinkly surfaces so while her brother was presenting his dishes, Lu Xinyi focused her attention at the cooking time of the buns.
