Add the marinade ingredients into a small mixing bowl (garlic, sugar, ginger, soy sauce and toasted sesame oil). Stir well to combine.
Using a sharp knife trim any tendon (silverskin) on the tenderloin and discard it.
Season gently with a little salt and a pinch of black pepper.
Place the tenderloin in a dish large enough and pour over the marinade. Rub the marinade all over the tenderloin.
Cover with a lid or plastic wrap/cling film and place in the fridge for ideally a few hours.
Place a frying pan or skillet over a medium high heat and add the vegetable oil. If you are cooking the pork in batches, then divide the oil accordingly.
Remove the pork tenderloin from the marinade and carefully slice it into medallions.
When the oil is hot transfer the sliced tenderloin to the pan and cook for about 2 minutes flipping over and cooking the second side for 1 – 1 ½ minutes.
The pork should be golden brown and gorgeous.
Remove from the pan and, if cooking in batches, keep warm until the rest are done.
Serve with rice and seasonal vegetables for a quick tasty meal.