First -- prep your ingredients! Cut the steak (against the grain) into thin strips. Mince the garlic. Peel and grate the carrots.
Get out your Instant Pot and plug in. Set the Instant Pot onto SAUTE mode and add the oil. Let heat up for about 30 seconds, then add the steak to the pot. Stir to start browning, then add the garlic. Stir occasionally until outside of meat is browned (about 3-5 minutes).
While meat is cooking, combine the soy sauce, water, sesame oil, and brown sugar and stir or whisk until well-combined.
Once meat is browned, turn off the saute function and add the grated carrots to the pot, and then pour the soy sauce/water/sesame oil/brown sugar mixture over the top. Stir to combine and then put the lid on the Instant Pot.
Make sure the pressure release valve is set to SEALING and put the Instant Pot on MANUAL mode, HIGH pressure for 10 minutes. (Instant Pot will take 5-10 minutes to come to pressure, then will start counting down).
While meat is cooking, combine the cornstarch and ⅓ cup water and set aside.
Once the meat is done, QUICK RELEASE to release the steam, and then remove the lid. Turn off the Instant Pot.
Pour the cornstarch/water mixture into the pot, and stir to combine. Turn the SAUTE mode on and cook for 2-3 minutes, until sauce has thickened.
Serve the meat over a grain of your choice, and top with sliced green onions if desired.