Dumpling Filling (Fully Cooked Pork Filling)

Name: Dumpling Filling (Fully Cooked Pork Filling)
Prep time: 15 min
Cook time: 10 min
Total time: 25 min
Cuisine: Chinese
Ingredients: 1000 g ground pork - 70% to 80% lean ((About 2.2 lbs)); 350 g napa cabbage - leaf part; 20 g ginger - minced; 50 g green onion - finely chopped; 100 g shiitake mushrooms ((Can be substituted with other mushrooms of your choice)); 1 large egg; 6 tbsp cooking oil ((I used vegetable oil)); 1 tbsp sesame oil ((Can be substituted with1 tbsp of vegetable oil)); ½ tsp salt; 2 tbsp regular soy sauce; 1 tbsp oyster sauce; 1 tsp chicken powder; 2 tbsp cooking wine ((optional)); 1 tsp sugar; ¼ tsp Sichuan peppercorn powder ((optional)); ¼ tsp white pepper powder ((optional)); 1 tbsp cornstarch ((or potato starch)); 2 tbsp water; 80 dumpling wrappers ((See my dumpling wrapper recipe))