Cut flank steak into thin strips, and coat in 2 Tbs corn starch
Turn instant pot on to saute.
Add oils, cornstarch coated flank steak, and garlic and ginger. Saute for 2-3 minutes, until meat is starting to brown.
Add in sauce ingredients (water, ground ginger, soy sauce, beef stock, brown sugar).
Secure lid for high pressure, set to sealed. Hit the "Keep Warm/Cancel" button to turn it off Saute
Then hit Manual, and manually set high pressure for 10 minutes.
After the 10 minutes is up, Quick release pressure. I like to put a rag over the valve, and turn it so it doesn't spit hot water out and burn someone.
Turn pot back to saute mode, and bring to a boil.
Whisk in additional 2 Tbs corn starch, get rid of all the lumps (you could make a slurry by removing some liquid from the pot and adding it to the corn starch, then add it back in), cook for 2-3 minutes allowing sauce to cook down some and thicken up.
Remove from pot, and serve over rice, garnished with sesame seeds and green onion.
Note: Can add broccoli during the last 2-3 minutes to get a light steam and have a complete meal with side.