Cut the bell peppers in half lengthwise, remove seeds and pith, and chop into bite-sized pieces.

Cut the pork into bite-sized pieces. In a bowl, combine pork with sake and soy sauce from the marinade ingredients. Massage lightly, then coat with potato starch.

In a separate bowl, mix all the seasoning sauce ingredients (sake, soy sauce, sweet bean sauce, and garlic).

Heat salad oil in a frying pan over medium heat. Add the pork and stir-fry until browned. Add the bell peppers and cook for about 2 minutes until softened.

Add the seasoning sauce to the pan and stir-fry to combine. Drizzle with sesame oil and mix briefly.