Make the bao buns: Combine warm water, 1 teaspoon sugar, and yeast; let activate for 5-10 minutes.

Sift flour, baking powder, and remaining sugar.

Knead yeast mixture into dry ingredients using a stand mixer with a dough hook until a rough dough forms.

Add shortening or oil and knead until smooth and elastic (5-7 minutes).

Cover and proof until doubled in size (30 minutes to 2 hours).

Prepare 10 parchment squares.

Punch down dough, portion into 10 equal pieces, and knead each briefly.

Roll each piece into a rectangle, fold in half, and place on parchment squares.

Proof for 30-45 minutes.

Steam in a pot of boiling water for 12 minutes until soft and pillowy.

Re-steam for 3 minutes before serving if stored in fridge.

Make the pork: Boil pork belly slices for 5 minutes; discard water.

Heat oil and brown sugar in a pan until sugar dissolves.

Sear pork belly slices on both sides until brown (2-3 minutes per side).

Deglaze pan with shaoxing wine and light soy sauce.

Transfer pork and sauce to a pot or Dutch oven.

Add dark soy sauce, ginger, garlic, scallions, and star anise.

Add water until pork is half-submerged.

Bring to a boil, then simmer covered for 60-90 minutes, stirring occasionally.

Check sauce consistency and reduce if necessary to a saucy glaze.

Assemble: Pull bao buns apart, brush with pork belly sauce.

Wedge in pork belly slices.

Garnish with scallions, cilantro, and sesame seeds.