Chop off the white part of the scallion, place in a container with a few slices of ginger, and 1 tbsp of Sichuan peppercorn. Add 1 cup of boiling hot water and soak for about 5 minutes. This spiced water will be used to marinade the pork filling.
Chop 12oz of shrimp into small pieces. Make sure the shrimp is fully deveined otherwise it will have an unpleasant flavor.
In a bowl, add 1.5 pounds of ground pork and chopped shrimp. To season this, add 1 tsp of salt, 1 tsp of white pepper, 1 tsp of Chinese five spices, 1 tbsp of oyster sauce, 1 tbsp of soy sauce, and 1 tbsp of sesame oil. Lastly, crack 1 egg into the bowl.
Drain the spiced water and add ⅓ cup to the pork mixture. Mix well until pork absorbs the water then add more. (I usually do it 3 times, which is adding ⅓ cup of water at a time.)Once adding all of the water, mix it vigorously. Add 2 tbsp of cornstarch to the filling, mix well. And then add some chopped scallion on the top, pour some hot oil over it and mix well until this scallion oil is fully absorbed.