Soak the glutinous rice and mung beans together for 24 hrs and then drain. Add 1 tsp Lee Kum Kee Chicken Bouillon Powder and 1 tsp oil, mix well. Split 1 salted egg yolk into 8 equal portions. Split the remaining ½ of a salted egg yolk into 8 small pieces (for garnishing).
Place pork into a bowl and mix in marinade ingredients. Whip the mixture in one direction until it is about to turn paste-like. Leave in refrigerator to marinate for 30 mins.
Divide the pork into 8 equal portions. Put ⅛ of a salted egg yolk into each portion and roll into a ball. Coat the ball with glutinous rice and mung beans then, add a small piece of egg yolk on top. Repeat with remaining pork portions.
Place the dumplings onto a plate and steam for 15–20 mins or until cooked. Sprinkle the diced spring onions and serve.