Put the pork on a large cutting board and very finely mince it with a sharp, heavy knife or cleaver until the fat is broken down; spread it out on the board into a thin layer (or use 2 large heavy cleavers to get the job done quicker!). Using a fine grater or microplane, grate the shallot, ginger, and bouillon cube over the meat. Sprinkle the five-spice, Shaoshing, salt, pepper, egg yolk, and cornstarch over the pork and use the knife or a spatula to mix the ingredients until well combined.
Put some cornstarch in a shallow bowl, and using your hands, roll the pork mixture into ping-pong ball sized balls and roll them in the cornstarch to lightly coat. Shake off the excess starch and transfer the meatballs to a plate.
Working with wet hands, put some of the soaked rice in your palm and roll the meatball in it with your hands, pressing gently, until it is evenly coated in rice. Continue rolling until the meatballs are all coated with rice.
Fill a wok 1/3 with water and bring to a boil over medium-high heat. Put a shallow flat bowl or plate with a lip into a bamboo steamer basket (make sure the plate is at least ½- inch smaller than the diameter of the basket) and evenly space the rice balls on the plate, being sure they do not touch each other. Cover the basket with the lid and lower it into the wok. Steam the meatballs, adding water to the wok as necessary to prevent the basket from scorching, until set and firm, 20 to 25 minutes.
Carefully remove the rice balls from the steamer and transfer them to a platter. Serve the meatballs with toothpicks on the side for skewering and dipping into vinegar, chili oil, or soy sauce.
NOTE: You can also put the finely chopped pork into a standing mixer fitted with a paddle attachment and whip it to breakdown the fat and make a smooth, tender meatball. Add the flavoring ingredients and whip slowly until combined before rolling and steaming the pearl balls. They can also be steamed on a vegetable steamer basket fitted inside a large pot with a lid.
Prep time: 15 minutes
Inactive prep time: 12 hours for soaking rice
Cook time: 25 minutes
Total time: 40 minutes