Bring a large pot of water into boil over high heat, carefully add in the pork belly, cook for about 5 minutes (to help get rid of excessive oil), remove the pork belly, drain well and cut into thick slices.
While the pork belly has been cooked in the water, mix dark soy sauce, sugar, cooking wine and water, set aside for later use.
Heat a pan over medium-high heat without adding oil, place the pork belly onto the pan, pan-fry for about 5 minutes until browned. (Pork belly will release a lot of oil during the cooking process, I discarded half of the oil and left the other half for stir-frying the other ingredients later when making this dish)
Stir in the king oyster mushroom, green and red peppers stir fry for about 2-3 minutes until cooked through.
Add in the garlic, cook for about 1 minute until fragrant.
Pour in the sauce made earlier, stir fry for another 2 minutes until sauce is thoroughly mixed into the other ingredients.
Top with chopped cilantro and red hot chili (optional) to serve!