Trim the beef and cut it into thin strips. For more tender meat, cut across the grain. Wash and cut the broccoli into bite sized pieces.

Tun your Instant Pot to "Saute" and add the oil. When hot, brown the strips of beef. It works best to brown it in two batches. Remove meat to a plate.

Add the water and bouillon to the pot. Scrape up all the brown bits on the bottom of the pot.

Stir in the pepper, soy sauce, brown sugar, sesame oil, garlic, and red pepper flakes. Add the beef and any juices on the plate.

Add the lid, set the vent to "seal", and select "Manual/High" for 10 minutes on the Instant Pot. When the cooking is done, use quick release to let out the steam.

Remove the lid and set the pot to "Saute" again. Whisk together the cornstarch and cold water until smooth.

Add the cornstarch slurry and broccoli to the pot. Cook for 5-8 minutes, or until the broccoli is tender, stirring occasionally.

Serve over hot cooked rice; garnish with sesame seeds if desired.