Turn on instant pot and select sauté. When it is hot, add in vegetable oil. Cook beef in 2-3 batches and sear the sides of the beef cubes till golden, 5 minutes for each batch. Do not overcook.
In a separate bowl, stir together brown sugar, soy sauce, chili paste, sesame oil, garlic, ginger, black pepper, rice wine vinegar, and broth. Add this mixture into the instant pot with the beef and add onion and carrot.
Seal the pressure valve, select manual setting, cook under high pressure for 20 minutes, around to cool for 10 minutes, then quick release.
Open the lid and set the pot to saute, add in broccoli and let cook in the broth for 1 minute.
In a small bowl, whisk together cornstarch and ¼ cup of water, mix thoroughly and stir into the broth. Keep stirring and let the broth thicken while frequently stirring, for around 3 minutes.
Sprinkle toasted sesame seeds and serve with scallion on top.
Serve with rice