In bowl or zip bag, combine the shaved beef, sesame oil, red pepper flakes, ground ginger, sliced onions, sliced green onion, brown sugar and soy sauce. Marinate for 1 hr or overnight if making ahead.
Place marinated beef, along with the juices, in instant pot for 10-15 minutes (depending on the cut of meat) Shaved beef I'd pressure cook it for 7-8 minutes on high pressure. When done release pressure for 10 minutes.
Be careful to leave plenty of space for steam.
Transfer to dish and serve along-side rice and various toppings.
Notes
Can be kept in an air tight container, in the fridge, up to 4 days. May be stored, cooked and frozen in zip tight bags. Can skip marination if pressed for time. May be reheated stove top over medium high heat in a pot or microwave for 30 second intervals.