1. Clean the bitter gourds and cut into pieces (2" length). Scoop out the seed and the inside part. Sprinkle the salt inside and outside part of the sliced bitter gourds. Leave it for 10-15 minutes, then wash with clean water.
2. In a medium-sized bowl, add ground pork, garlic, coriander roots, soy sauce (1 tbsp), oyster sauce (1 tsp) and sugar (1 tsp). Knead until all ingredients mixed well. Then stuff the ground pork inside the sliced bitter gourd.
3. Heat chicken stock (or water) in a pot over medium heat. Add stuffed bitter gourds, shitake mushrooms, carrot, soy sauce (1 tbsp), oyster sauce (1 tsp) and sugar (1 tsp). Wait until boiling then turn down the heat to low level. Let simmering for at least one hour (the longer time the better taste, recommend 1-2 hours).
4. Remove from heat and transfer to a nice bowl. Sprinkle with white pepper powder and garnish with coriander leaves. Serve immediately with hot steamed rice.