Dice the tofu into 1cm cubes.
Finely chop the onion, green onion, and pork.
Heat cooking oil in a pan and stir-fry the green onion and pork.
Once the pork is cooked, add onion and minced garlic, and stir-fry together.
Season with soy sauce, oyster sauce, and pepper.
Add the tofu and gently mix while stir-frying.
Add water and starch water to thicken the sauce.
Transfer to a bowl and serve.