Step 1

Prepare the beef: In a large bowl toss the flank steak strips with the cornstarch together and let them sit for 5 minutes. This will ensure the cornstarch penetrates the beef.

Step 2

Make the sauce: In a medium size bowl add the rice vinegar, soy sauce, water, garlic, ginger, brown sugar, red pepper flakes and whisk well. Set aside.

Step 3

Turn your Instant Pot to the saute setting. (See your manufacturer's guide for detailed instructions on how to use your instant pot.)

Step 4

Sear the beef: Add half of the sesame oil to the pot. When the oil is hot add half of the flank steak and cook 2 to 3 minutes until it starts to brown. Remove from the pot and repeat with remaining sesame oil and beef. Return all the beef to the pot and press the cancel button on your Instant Pot.

Step 5

Pour the sauce over the beef and stir well.

Step 6

Cook: Close the lid (follow the manufacturer's guide for instructions on how to close the instant pot lid). Set the Instant Pot to the Manual (high pressure) setting and set the timer to 10 minutes.

Step 7

When cooking is complete, use a quick release to depressurize.

Step 8

Stir in the green onions and garnish with sesame seeds. Serve over rice.