Start by cutting the steak and broccoli into bite-sized pieces. Cut the steak against the grain for the most tender meat.
Prepare the sauce by whisking together all the sauce ingredients in a bowl.
Heat 1 tablespoon of oil in a large pan over medium heat. Add the steak and cook until it’s almost done, about 4 minutes. Don’t worry if there’s still some pink inside.
Remove the steak from the skillet and add the remaining tablespoon of oil. Toss in the broccoli, garlic, green onion, and water. Stir everything together and cook for 2-3 minutes.
Return the beef to the skillet and pour the sauce over the mixture. Stir well to coat everything evenly. The sauce will thicken up nicely.
Let the beef and broccoli simmer in the sauce for 5-6 minutes, then turn off the heat.
Taste and adjust the seasoning if needed. Serve the beef and broccoli over rice, sprinkle with sesame seeds for garnish, and enjoy your homemade takeout-style dinner!