1. Rinse preserved salted and sweet vegetables several times, soak in water for 45 minutes, rinse, squeeze dry, and chop.
2. Heat wok with oil, fry the preserved salted and sweet vegetables, add mince pork, and fry until the meat is separated. Add seasoning and stir-fry until the meat is cooked. Add toasted sesame seeds and stir well. Dish up and set aside.

For the Soup

1. Mix all bao dough ingredients together and knead until smooth, dusting with flour if needed (knead for about 10 minutes). Cover and rest for 5 minutes.
2. Roll the dough into a cylinder, cut into 15 pieces (about 35g each).
3. Flatten each dough piece into a small disc with a rolling pin, making the edges thinner and the center thicker.
4. Wrap the dough with filling, sprinkle with toasted sesame seeds, and place on a small square of parchment paper.
5. Place the dough bao in a steamer with water (not yet boiling), cover, and proof for 15 minutes.
6. Bring water to a boil and steam the buns for 12 minutes.
7. Turn off heat, leave the lid slightly open for 3-5 minutes before removing completely.