Add the flour, powdered sugar, baking powder, salt, and milk to a bowl. Stir the yeast into the water and then pour it into the bowl. Knead everything by hand until the dough no longer sticks to the edges of the bowl. Cover the bowl and let sit for 1 hour.
Roll the dough out on a floured work surface and use a 5½ inch dish to cut out two circles. Brush the dough circles with oil and then fold each one over in the middle so that you have two semicircles.
Line a sieve with parchment paper and put it inside a pot. Place the dough on the parchment paper, cover the pot with a lid, and cook over a hot, but not boiling, water bath for 15 minutes. The dough should expand in size and slightly darken.
While the bao buns cool, prepare the filling. Heat the sesame oil in a pan and sweat the garlic together with the ginger and chili pepper. Add the cubed chicken breasts and cook it all together.
Add the honey and lime juice and let the meat marinate in the sauce. Mix the soy sauce and corn starch together in a separate bowl and add the end result to the pan.
Coat the bao bun with sriracha mayo and fill it with Chinese cabbage, carrot strips, mung bean sprouts, and red onion slices before adding the meat. Finally, garnish the whole thing with chili pepper slices, peanuts, and coriander.
