Stuffed bun with pork and preserved mustard greens (Meicai)

Ingredients: Wheat flour 33%, pork 28%, water, preserved mustard greens (Meicai) 4%, spring onion, ginger, sugar, soy sauce (soybeans, wheat flour, preservative [E202]), rice wine (wheat flour), oyster sauce (oyster extract, soybeans, wheat flour), monosodium glutamate (E621), white pepper powder, salt, sesame oil, black pepper, sodium bicarbonate (E500), yeast, rice, baking powder (raising agent (sodium acid pyrophosphate (E450), sodium carbonate (E500), sodium bicarbonate, sourdough starter (wheat)