Turn on the "sauté" function of the pressure cooker, press "adjust" once to switch to "more" for browning. Add vegetable oil to coat the bottom.
Once the oil is hot, add pork belly and give it a stir so that it's not sticking to the bottom. After 3-5 minutes, there's liquid coming from the pork belly. Let it cook until the liquid evaporates. This is to make sure it doesn't dilute the seasonings that will be added later on and allow the flavors to quickly penetrate the pork belly.
Add the following ingredients.
Mix well and cover with the lid.
Turn on the "manual" function, set the timer to 20 minutes or 30 minutes if you have more time. Natural OR quick release after done. Skim off the fatty oil from the top.
Turn on the "sauté" function, and "adjust" to "more". This is to thicken the sauce and darken the pork belly. The longer the pork is sautéed, the darker color it gets and the sauce becomes more concentrated. This is up to your preference. Add light soy sauce or salt to taste. If you want to thicken the sauce, mix 2 tbsps water with 1 tbsp corn starch and add it to the pork and cook until the sauce is thickened.