Trim off the fat and silver skin from the pork shoulder. Cut the meat into bite-size then blend with a food processor until smooth. Get the freshest meat possible and don't use pre-ground pork because the texture does not come out the same.
Season the ground pork with salt, soy sauce, sugar, baking soda, garlic powder, and freshly ground white pepper
Add crushed ice and stir the ground pork within one direction for 8 minutes. You can do this by hand or by using a standard machine. Stirring the meat will create a lot of heat, adding ice will make sure your meat stays fresh and cold.
In a blender, add garlic, ginger, scallion, and cold water. Blend this into a puree and let it go through a sieve. Mix the aromatic liquid with 150 grams of sweet potato starch thoroughly.
Add the sweet potato starch puree mixture into the meat in 3 batches and stir within one direction for 5 minutes or until the meat becomes sticky. You can do it by hand or using a stand mixer.
Add the stock to a pot and bring to a simmer. Spread the meat mixture onto a flat plate. Use a chopstick to scrape the meat into the stock little by little. Between every scrape, dip the chopstick into the stock to prevent sticking.
Bring the pot to a boil then continue to cook for 3-5 minutes.
Meanwhile, put all the ingredients to assemble the soup in a big serving bowl then pour in all the meatball soup. Taste to adjust the flavor.