Start by browning your lean ground beef and diced onions right in the Instant Pot using the "Sauté" setting. Break the beef apart as it cooks. Once cooked through, carefully drain any extra fat to keep it healthy, then turn off the pot.
In a separate small bowl, whisk together the simple sauce ingredients: garlic powder, low-sodium soy sauce, beef broth, a touch of brown sugar, sesame oil, red pepper flakes for a little kick, and ground ginger. Pour this flavorful sauce right over your browned beef, giving it a good stir.
Now for the rice! Place a trivet inside the Instant Pot over the beef mixture. In an Instant Pot-safe baking dish (like a bundt pan that fits), combine your white rice with 1 1/4 cups of water. Gently lower this dish onto the trivet.
Close the lid, seal the vent, and pressure cook on High for just 4 minutes. After cooking, allow the pressure to naturally release for 5 minutes, then carefully quick-release any remaining pressure until the valve drops.
Carefully lift out the rice dish and the trivet from the pot. Fluff your perfectly cooked rice with a fork.
To thicken the delicious beef sauce, mix the cornstarch with 2 tablespoons of water to create a smooth slurry. Stir this into the beef mixture in the pot, and the residual heat will gently thicken the sauce to perfection.
Spoon the amazing Korean ground beef mixture generously over your fluffy rice. Serve immediately and enjoy a wholesome, easy meal!