Trim the fat and gristle from the beef and put to one side.
Peel and thinly slice the ginger and the garlic.
Rinse and dice the spring onion.
Place the beef in the Instant Pot and set the Instant Pot to the sauté function. Then using your olive oil give it a quick blast until it is 40% cooked. Then remove from the Instant Pot and place on a clean plate.
Next sauté the garlic and ginger for a minute until they have a little colour. Add soy sauce, brown sugar and 1 cup of water. Stir until well mixed.
Return the beef to the Instant Pot, add the lid, set the valve to sealing and cook for 12 minutes on the manual setting.
After 12 minutes use quick pressure release (QPR) so that the cooking process stops immediately and turn off the Instant Pot.
In a mixing bowl use the corn flour and a small amount of water, mixing until it is smooth, making sure you don’t add too much water.
Turn on the Instant Pot and place it back on sauté. Add the corn flour mixture (a bit at a time) and stir it in until you have a thicker sauce for your Mongolian Beef.
10. Pour into dishes and scatter your chopped spring onion over the top.