Mix the flour, yeast, baking powder, sugar, and salt together in a large bowl or the bowl of a stand mixer fitted with a dough hook. Stir in the milk, water, and oil to form a rough dough.

Knead the dough for about 10 minutes until it is smooth and stretchy.

Place the dough in a lightly oiled bowl, cover it, and set aside to rise until doubled in size—about 1 hour.

Once risen, punch down the dough gently and knead briefly before using a scale to divide it into 10 even pieces.

Roll each piece into a ball by gathering the edges up and pinching them together until they are neat.

Using a rolling pin on a lightly floured surface, roll one ball out into an approximately 9 x 12 cm oval. Lightly brush with oil before folding it in half to form a semicircle.

Place each bao on squares of baking paper and arrange them spaced apart in the steamer basket. Cover and let rise again for about 30–40 minutes until puffy.

Place the steamer over a wok or frying pan filled with cold water ensuring it doesn’t touch the buns directly. Place the lid on top.

Bring water to boil over high heat then reduce heat to medium and steam for about 10 minutes.

Without removing the lid, remove from heat and let sit for another five minutes before serving.