In a large mixing bowl or stand mixer, combine all-purpose flour, sugar, instant yeast, and baking powder. Gradually add warm water while mixing until a shaggy dough forms.

Transfer the shaggy dough to a floured surface or keep it in the stand mixer. Knead for about 8 minutes on medium speed or 12 minutes by hand until smooth and elastic.

Shape the kneaded dough into a smooth ball and lightly brush with oil. Place in a clean bowl, cover with plastic wrap, and let rise for 1 to 2 hours.

While the dough is rising, prepare parchment paper squares for steaming.

After rising, punch down the dough, divide into 12 equal portions, roll into discs, and shape into balls on parchment squares.

Arrange dough balls in a bamboo steamer, cover, and let rise for 30 minutes to 1.5 hours.

Bring water to boil in a pot, then reduce heat. Place the bamboo steamer over the pot and steam the buns for 12 minutes.