Spread pork belly slices, season with salt and pepper, and coat with potato starch.

Overlap two slices slightly and roll tightly to avoid gaps.

Heat salad oil in a pan and sear the rolled pork until browned on all sides.

Wipe off excess oil, then add soy sauce, sake, mirin, water, chopped green onion, and sliced ginger.

Bring to a boil, reduce to low heat, cover with a drop lid, and simmer for 15 minutes. Let cool with the lid on.