In a small mixin bowl add the warm water (about 30 seconds in the microwave), sugar, and yeast whisk to combine, set aside until bloom, 10 minutes.
In a large bowl, whisk together the flour, baking powder, and salt. Add the yeast mixture and vegetable oil in the center and stir with a spatula until dough begins to form. Transfer the dough to sillicon mat or a clean surface and knead until smooth and elastic, about 5 minutes. Use the extra flour in case the dough sticks to the surface or your hands.
Next shape into a ball lightly cover with sesame oil and place on the bowl. Cover with plastic wrap. Place in a warm place to let it rise (doubled in size) 2 hours (I use my oven or microwave to let the dought rise)
Once the dough has risen, place it on to the sillicon mat or a floured surface. Dividing the dough in half, then cut each half into half until you have 12 pieces. Roll each piece into a ball and cover with a wet towel.
Working one ball at a time, flatten with your palm first, then on a lightly floured surface use a small rolling pin to roll the dough out to about 5-inch round. Brush the top of the dough with sesame oil and place in a square of parchment paper, set on a baking sheet. Repeat the process with the remaining dough. Cover the dough with a wet towel or plastic wrap the same you use before and let rest for 10 extra minutes.
Now bring a pot of water to a boil place the bamboo steamer on top. Important to work in batches, transfer a few of the dough buns at a time to the steamer, making sure the buns are not too crowded. Cover the steamer and steam the buns for 8 minutes or until the buns puff up and form a skin on the outside. Carefully, lift the lid and remove buns from the steamer. Repeat until all the buns are done, making sure to keep the steamed buns warm by covering with a towel.