Preheat a skillet at medium heat. No need to add oil, just transfer all of the marinaded pork belly to the skillet. Cook until the outside caramelized. Leave the pork belly on a plate for later use.
Leave some pork grease for cooking the vegetables, while transferring the rest into a jar or a paper bowl(if discard). See the FAQ section below for more details about how to deal with pork grease.
Sautee some garlic in the pork grease. Once you can smell the aroma, add the carrots in and cook until tender. About half a minute later, add bell pepper and onion into the pan.
To season the vegetables, add 1 tbsp of soy sauce. Add pork belly into the pan, mix well with vegetables.
Sautee for about 1 minute over high heat. Then transfer to a serving dish. This pork belly stir fry goes really well with rice!