Instant Pot Mongolian Beef is a delicious dish made with flank steak and has a flavorful sauce. The beef is tender and the sauce is thick and rich, perfect to serve over rice.
Add the corn starch to a large plastic zip closure bag, or to a bow. Add the beef slices and coat them in the corn starch. Set them aside.
Turn on the pressure cooker's highest Sauté setting. When it is hot, add the oil.
Add the beef in one layer and brown both sides. You will need to do this in two batches so the meat isn't crowded. You are just browning the meat, it will not be fully cooked at this point. Remove to a plate and set aside.
While the beef is browning, to a large measuring glass/cup add the garlic, ginger, soy sauce, rice wine, sesame oil, red pepper flakes, and 1/4 cup of the water. Mix well. Set aside.
Add remaining 1/2 cup of water to the pot and use a wooden spoon to scrape up all of the browned bits from the bottom of the pot (deglaze).
Add the sauce and green onions to the pot and stir.
Cancel the sauté setting and add the beef and any liquid on the plate back into the pot.
Close the lid and set the steam release knob to the Sealing position.
Press the Pressure Cook/Manual button or dial, then the +/- button or dial to select 10 minutes. High Pressure. The pot will take a few minutes to come to pressure.
While the beef is cooking, mix together the corn starch and water for thickening. Set aside.
When the cook cycle has finished, turn off the pot and let it sit undisturbed for 10 minutes (10 minute natural release). Then turn the steam release knob to the Venting position to release the remaining steam/pressure.
When the pin in the lid drops back down, open the lid.
Add the brown sugar, stir well.
Turn on the sauté setting (normal heat), then stir the beef and sauce. When it starts to simmer, pour in the corn starch slurry. You may not need to use it all. Then turn off the pot.
Serve immediately over some hot cooked rice.