Step 1

In a bowl, whisk together soy sauce, mirin, sugar and grated ginger, set aside.

Step 2

Put the thinly sliced beef into a medium ziploc bag and pour the sauce mixture over the beef in the bag, gently squeeze the bag to mix the sauce well with the beef.

Step 3

Seal and place the bag in the fridge, marinate for at least 30 minutes.

Step 4

Heat oil in a pan over low heat until shimmering, add in the onion and sauté about 5 minutes or until soft and lightly browned.

Step 5

While the onion is being cooked, transfer the beef into a large mix bowl. Mix potato starch with water and pour the starch water and sesame oil over the beef, gently rub the beef to make sure it is well coated.

Step 6

Add the marinated beef into the pan on top of the sautéed onion first, then spread it out evenly over the pan with a pair of chopsticks and let cook for 4-5 minute until cooked though, stirring occasionally.

Step 7

Sprinkle with sesame seeds and chopped scallion, continue cooking for 30 seconds.

Step 8

Transfer to a plate to serve with rice or vegetable.