Cut the peppers into halves, remove seeds and stalk. Slice each half into four pieces.
Heat the sesame oil in a frying pan over a medium heat. Place the peppers skin-side down and cook for 7–8 minutes, turning them over and occasionally pressing them down with chopsticks (or a fork) until evenly charred.
Add the marinade to the frying pan, cover with a lid, and steam-cook over a low heat for about 3 minutes. Remove the lid, turn the peppers, and continue to steam-cook for a further 2 minutes.
Serve warm, at room temperature, or chilled with the sauce.