Cut the pork loin into bite-sized pieces.
Julienne the onion and bell pepper.
Mince the green onion and garlic.
Heat cooking oil in a pan and stir-fry the green onion and garlic.
Add the pork loin and stir-fry until cooked through.
Add the onion and bell pepper, and stir-fry together.
Season with oyster sauce, soy sauce, and pepper.
Pour in 50ml of water and stir-fry.
Serve everything over rice to finish.