Cut the pork belly into bite sized pieces, trying to cut them thin. Prep all vegetables.
Heat a pan until very hot. Add pork belly and cook over medium heat, searing as if grilling.
When the pork is about 80% cooked and has released a lot of fat, remove excess oil with paper towel.
Increase heat to high. Add spring onion and cook until lightly charred.
Add sugar and mirin first, tossing to coat the pork evenly.
Add onion and stir fry for about 3 minutes.
Drizzle soy sauce around the edge of the pan, add oyster sauce, and stir fry for another 3 minutes.
Add garlic and black pepper. Toss quickly for about 2 minutes to finish.
