Cut the flank steak into thin slices. Ensure the beef is sliced thin to bite-size pieces.

In a medium-sized bowl, place the beef strips. Pour the cornstarch over the sliced beef. With your hands or a large spoon, mix the thin slices well until every piece of the steak is well coated. 

In a medium bowl, mix together the soy sauce, beef broth, brown sugar, white wine vinegar, ginger, olive oil (1 TBSP), garlic, ginger, and red pepper flakes. 

Select the “saute” setting on the Instant Pot. Once hot pour in enough olive oil to coat the bottom of the pot.

If there isn’t enough oil, the cornstarch from the meat will stick to the pan and the Instant Pot will show a burn notice.

After the oil is hot, add beef a little at a time. Brown each piece of meat. Once brown, remove from the Instant Pot and put to the side until all of your meat is browned. 

Once all of your meat is browned, turn off the “saute” mode.

Return all of the meat to the inner pot, and pour the prepared sauce over it. Put the Instant Pot lid on, and lock the lid in position.

Close the sealing valve. Set the Instant Pot to cook on High Pressure for 10 minutes.

After the pressure cooking time is done, use a long wooden spoon to open the sealing valve to allow the steam to escape.

Once all of the steam is released and you can safely remove your Instant Pot lid, do so carefully.

Toss fresh green onions into the Instant Pot and stir. Serve the Mongolian Beef with a garnish of sesame seeds.