Photo: Wang Yu Ching / Office of the President, ROC (Taiwan) (CC BY 2.0) via Wikimedia Commons · source
A soft folded steamed bun around soy-braised pork belly, pickled mustard greens, sweetened peanut powder and cilantro. Lan Jia in Taipei asks if you want lean, fatty or half-and-half.
For the buns: 300 g (2 1/2 cups) all-purpose flour, 4 g (1 1/4 tsp) instant yeast, 1/2 tsp baking powder, 1 1/2 tbsp sugar, 160 ml (2/3 cup) warm milk, 1 tbsp neutral oil, plus oil for brushing
For the pork: 600 g (1 1/4 lb) skin-on pork belly, in 1.5 cm (1/2 in) slices, 4 tbsp soy sauce, 2 tbsp rice wine, 2 tbsp rock or brown sugar, 4 slices ginger, 3 cloves garlic, 2 star anise, 300 ml (1 1/4 cups) water
For the toppings: 150 g pickled mustard greens (suan cai), rinsed and chopped and stir-fried 2 minutes with 1 tsp sugar and a little chili; 6 tbsp roasted peanuts ground with 2 tbsp sugar; a bunch of cilantro
How to make it
Braise the pork (1 1/2 hr): Brown the pork slices in a pot 3 minutes a side, add the soy, wine, sugar, ginger, garlic, star anise and water, and simmer gently, covered, until very tender, about 1 1/2 hours. Uncover for the last 15 minutes to thicken the sauce.
Make the dough (15 min, then 1 hr): Mix the flour, yeast, baking powder and sugar, add the milk and oil and knead 8 to 10 minutes until very smooth. Cover and rise until doubled, about 1 hour.
Shape (15 min, then 20 min): Divide into 10. Roll each into an oval 12 x 8 cm, brush the top lightly with oil, and fold in half over a chopstick (remove it) so the halves don't stick. Set each on a square of parchment and rest 20 minutes.
Steam (10 min): Steam over boiling water, covered, 10 minutes. Turn off the heat and wait 3 minutes before opening so they don't collapse.
Fill: Open each bun, add a slice of pork with a little sauce, a spoon of mustard greens, a good pinch of peanut sugar and cilantro.
Tips
Freeze steamed buns and re-steam 5 minutes from frozen.
No suan cai? Use quick-pickled cucumber, as BAO in London does with their pickles.