Put olive oil in the base of the Instant Pot and select the saute function. When the oil begins to sizzle, add the lean ground beef and chopped onion; cook until the onions are translucent and the ground beef is browned.

Add the garlic and cook for 30 seconds more. Turn off the saute function.

Stir in the water, soy sauce, brown sugar, sesame oil, ground ginger, and red pepper flakes; stir until the sugar is dissolved and all the browned bits on the pot are scraped up. Lock the lid in place. Select High Pressure and set the cooking time for 4 minutes.

While the ground beef is cooking, cook, steam, or microwave the broccoli until tender. The microwave will take about 3 to 4 minutes with 1/4 cup of water.

Once the ground beef has cooked, naturally release the pressure for 10 minutes before quickly releasing any remaining pressure. Once the pin drops, remove the lid.

In a small bowl, combine cornstarch and water; whisk until smooth. Select the saute function on the Instant Pot and stir the mixture into the beef. Continue to cook until it has thickened. This should take seconds. Add the steamed broccoli and serve over hot, cooked rice and garnish with sesame seeds.