Soak the Pork Belly (500 gram) in clean water for around 2 hours. Change water twice during the process.
Put the Sichuan Peppercorns (1 teaspoon), Star Anise (2), Cinnamon Stick (1), Whole Clove (5), Galangal (1 piece), Bay Leaf (2), Fennel Seeds (1 teaspoon), Fructus Amomi (1), Dried Ginger (2 piece), Sand Ginger (1 piece), Whole Nutmeg (1), and Dried Tangerine Peel (1 piece) in cheese cloth and tie the top.
In a pot, add pork belly, the spice bag, Fresh Ginger (1 inch), Crystal Sugar (2 1/2 teaspoon), Scallion (5), Salt (1 teaspoon) and Dark Soy Sauce (3 tablespoon). Pour in enough Water (to taste) to cover the pork belly. Bring to boiling then turn now the flame and simmer for 2 hours.
Turn off the fire and then soak the pork belly within the soup for at least 2 hours. Reheat it before assembling.
To make the bun, mix Baking Soda (1/2 teaspoon), Instant Dry Yeast (1/2 teaspoon), and All-Purpose Flour (350 gram). Stir in Water (140 milliliter). Stir the flour with chopsticks. Knead the dough until smooth. Cover with a wet cloth to rest for 30 minutes to 45 minutes, until the dough increase 1/3 in size.
Knead the dough again to pinch the air out. Then roll the dough into a uniform long log around 5 cm in diameter. Cut the long log into 6 equal portions.
Shape the divided dough into a long, flat log, then roll up the log.
Press the rolled log down and roll it into a disc that is 1/2-inch (1 1/2cm) thick. Shape it to a bowl with a hand.
Preheat oven to 190 degrees C (375 degrees F).
Heat up a pan. Place the bowl shaped dough in a pan to fry until slightly brown over medium fire. Turn over to fry the second side. Repeat the process to finish all the buns.
Transfer the buns to a baking sheet. Bake for 10 minutes so the breads are completely cooked through.
Take out the meat and finely mince. If you like, add Fresh Cilantro (to taste) and Ground Cumin (to taste).
Cut 2/3 of the bun from the middle. Lay minced pork and other ingredients within the bun. Serve and enjoy!