Instant Pot Mongolian Beef

1 For the most tender texture, slice the sirloin thinly against the grain. Placing the steak in the freezer for about 15 minutes before slicing can make this easier.
2 Add soy sauce, water, brown sugar, garlic, ginger, and sesame oil to the Instant Pot. Stir to combine.
3 Add the sliced beef and onions on top and gently press the beef into the liquid.
4 Close the lid and cook on high pressure for 10 minutes. Once cooking is complete, carefully perform a quick release.
5 Turn the Instant Pot to sauté mode and stir in the cornstarch slurry. Let the sauce bubble for 1 to 3 minutes until thick, glossy, and able to coat the beef.