In a stand mixer, combine 4 cups of all-purpose flour, 2 tablespoons of sugar, 2 teaspoons of instant yeast, and 1 teaspoon of baking powder. Gradually add 1 to 1.5 cups of warm water while mixing until a shaggy dough forms. Knead on medium speed for about 8 minutes, then switch to hand kneading for another 2 minutes until the dough is smooth and elastic.

Shape the dough into a ball, then lightly oil the surface to prevent sticking. Place the dough in a bowl, cover it tightly with plastic wrap, and let it rise in a warm, draft-free area for about 1 to 2 hours.

After the first proofing, punch down the dough gently to release any air. Divide the dough into 12 equal portions, shaping each piece into a round disc to eliminate air pockets. Form smooth balls and place each on a square of parchment paper.

Arrange the shaped buns in a bamboo steamer, making sure to leave space between them for expansion. Cover the steamer with a clean kitchen towel and let the buns rise for an additional 30 minutes to 1.5 hours.

While the buns are proofing, bring a pot of water to a rolling boil, then reduce to medium-low heat. Place the bamboo steamer over the pot and steam for 12 minutes.