Combine flour, yeast, baking powder, and sugar in a bowl, sift if preferred, into mixer bowl.

Turn on slow speed and gradually add in milk.

Mix for 1 minute, then turn speed up and mix for 6 more minutes.

Knead dough lightly into a dome shape and then place in a lightly greased bowl with damp towel to cover and let rise for 1 1/2-2 1/2 hours.

Combine and repeat above steps for darker dough mixture.

Begin making marinade/sauce for pork by combining all sauce ingredients. Let sit for 30 minutes after combined.

Begin cooking pork when you have about 10 minutes left for your sauce in a wok or pan at high/med-high heat, breaking into small pieces. Cook until done.

Add sauce mixture and cook on high until it coats evenly. Reduce heat and simmer for 3 minutes.

After dough has risen, remove from bowl and flatten, folding the top over itself twice, ending with a log.

Repeat for darker side of the dough.

Cut a small piece of dough from each log, and combine, rolling together. Fold/roll into a spiral, and repeat 3 times.

Form dough back into a ball after combined to desired marble, and roll it flat.

Once relatively flat, grab and lift one side and begin rolling out, spinning dough as you roll.

Place carrot(optional) and pork mixture in the center, and begin pinching the outside together working in a circle motion until completely sealed. Pinch and twist.

Form back into ball, then place on parchment paper.

Fill steamer basket, and then turn heat on high until boiling, then lower to medium-low and cover with lid for 10-12 minutes depending on size of dumpling. (Cover glass and metal lids with towel to prevent condensation drips.

Let sit in pan for 2 minutes, then carefully remove.

Enjoy your perfectly made Xi'an inspired Steamed Buns!