01 - Toss the sliced beef with 1 tablespoon cornstarch until evenly coated.
02 - In a medium bowl, whisk together soy sauce, beef broth, brown sugar, sesame oil, garlic, ginger, rice vinegar, and red pepper flakes.
03 - Add the beef to the Instant Pot, pour the sauce mixture over, and stir to combine. Seal the lid, set valve to Sealing, and cook on high pressure for 10 minutes.
04 - Quick release pressure, open lid, add broccoli florets, reseal, and cook on high pressure for 1 additional minute. Quick release again.
05 - Mix 2 tablespoons cornstarch with 2 tablespoons cold water to create a slurry. Stir into the pot, turn on Sauté mode, and cook for 2-3 minutes until sauce thickens.
06 - Serve hot, garnished with sesame seeds and sliced green onions.