Pour the flour into the bowl of a stand mixer. Add the baking powder, instant yeast, and granulated sugar. Click the bowl into a stand mixer fitted with a whisk attachment and whisk of medium until all the ingredients are thoroughly integrated.
Remove the whisk and replace it with a dough hook. Slowly stream in 1 cup of Luke warm water and 2 1/2 tablespoons of vegetable oil. Leave the mixer to work the dough for 7-9 minutes. The dough should look uniform and silky to the touch.Things will look dire. It will look like there is not enough liquid to form a cohesive dough, but there is. Bao dough is considerably dense, so don’t expect to be pillowy and soft like bread dough.
Finish the dough off by kneading it by hand for 5 minutes. Once the dough is where you want it, grease a bowl with neutral oil and transfer the dough to the bowl. Cover with plastic wrap or a tea towel and set aside to rise for about an hour and a half or until doubled in size.
Once the dough has risen, punch it down and knead it for 5 minutes. We want to work all the air bubbles out of the dough. This step is crucial. If you skimp on the kneading your bao will not have the smooth unblemished surface we’re looking for.
When the dough is thoroughly kneaded, roll it out to a 1/4 of an inch thickness. Using a cup of a 3” biscuit cutter, cut 12-13 circles out of the dough. Place each circle on a 4x4” piece of parchment paper and brush one half of each circle with sesame oil, before folding the naked half over top. Really press on the bun to flatten it out. Transfer the finished bao to a baking sheet and cover with a tea towel. Let rise for 30 minutes.
Bring 2 inches of water to a boil in a large wok. Place 3-4 buns in a bamboo steamer and place in the center of the boiling water. Reduce the heat to medium and steam the buns over rapidly simmering water for 7 minutes. Repeat until all the bao are steamed.