In a medium bowl mix together soy sauce, sugar, onion, garlic, ginger, sesame seeds and oil. Add pork and turn to coat.
Cover and refrigerate for 3 hours, turning and basting often.
Preheat oven to 190 degrees C.
Remove pork from marinade, reserving marinade and transfer pork to a roasting pan.
Bake in preheated oven until internal temperature reaches 145°C.
Cut into 6mm thick slices.
Boil reserved marinade for 3 to 5 minutes. Serve with pork strips.