In a medium mixing bowl, combine the thinly sliced flank steak with soy sauce, oyster sauce, and cornstarch. Mix thoroughly until the beef is evenly coated. Cover and let it marinate at room temperature for a minimum of 15 minutes.
Set your Instant Pot to the sauté setting and allow it to heat up. Pour in the vegetable oil. Once hot, add the minced garlic and ginger, sauté for 1-2 minutes until they become fragrant and slightly golden, stirring frequently to avoid burning.
Carefully add the marinated beef to the pot, spreading it out in an even layer. Sauté the beef for about 5 minutes, stirring occasionally, until it starts to brown and caramelize.
Pour in the beef broth, using a spatula to scrape up any browned bits from the bottom of the pot. Close the Instant Pot lid, ensuring that the pressure valve is set to the sealing position. Select the high-pressure cooking setting and cook for 10 minutes.
After cooking, perform a quick release by carefully turning the pressure valve to the venting position. Wait for the steam to escape completely before opening the lid.
Stir in the broccoli florets into the beef mixture. Close the lid again and select the sauté function; cook for an additional 3-4 minutes, or until the broccoli is tender-crisp and vibrant green, stirring occasionally.
Drizzle with toasted sesame oil and mix well to incorporate. Taste and adjust seasoning with salt and black pepper as needed.
Spoon the Beefy Broccoli Bash onto serving plates. Garnish generously with sesame seeds and sliced green onions for added freshness and crunch before serving.
Notes
Serve over jasmine rice or quinoa for a wholesome meal.