Place pork belly, green onion, and ginger in a pressure cooker. Add enough water to cover the pork. Heat on medium until pressure builds, then reduce to low and cook for 20 minutes. Allow pressure to release naturally.

Remove green onion and ginger. Take out the pork and rinse under running water to remove scum. Place pork skin-side up in a tray, cover with plastic wrap, and refrigerate for 1 hour. Strain the pork broth into a heatproof container, cool, and refrigerate for 1 hour to remove fat.

Cut the pork belly into 2cm thick slices.

Clean the pressure cooker. Add all seasoning ingredients and mix well. Place the pork slices into the mixture. Heat on medium until pressure builds, then reduce to low and cook for 30 minutes. Allow pressure to release naturally.

Remove pork, star anise, and ginger slices. Heat the sauce on medium and add cornstarch slurry. Stir until the sauce thickens.