This bread dough is twice risen, first with yeast and then with baking powder,which is kneaded into a dough,making it very light and fluffy.If you are into  business selling siopao ..I would definitely recommend  this dough recipe.

3 tbsp sugar

1 cup warm water

1 1/2 tsp dried yeast

3 1/4 cups all purpose flour

2 tbsp oil

1 1/2 tsp baking powder

DISSOLVE the sugar in the water,then add the yeast,Still lightly,then set aside for 10 minutes,or until foamy.

Sift the flour into a bowl and add the yeast mixture and the oil. Using a wooden spoon,mix the ingredients into a rough dough.Turn themixture out onto a lightly floured surface and knead 8-10 minutes,or until the dough is smooth and elastic.If it is very sticky, knead in a little more flour- the dough should be soft. Lightly grease a bowl with the oil. Place the dough in the bowl and turn it so that all sides of the dough are coated. Cover the bowl with a damp cloth and set aside to rise in a draft-free place for 3 hours.

UNCOVER the dough,punch it down,and turn it out onto a lightly floured surface . If you are not using the dough right away,cover it with plastic wrap and refrigerate.

WHEN YOU are ready to use the dough,flatten it and make a well in the center. Place the baking powder in the well and gather up the edges to enclose the baking powder. Pinch the edges to seal. Lightly knead the dough for several minutes to evenly incorporate the baking powder,which will activate immediately.