Cut beef in one half to one inch strips about 3 inches long and set aside.
Add sesame seed oil to a large skillet brown at medium heat. Once the oil is heated, add onions, garlic, ginger, and sesame seeds and heat until slightly darkened and fragrant (about 2 minutes). Add soy sauce, orange juice and brown sugar to heat and stir to mix completely.
Mix the cornstarch with water to make a thick slurry and add to the mixture to thicken. Add the beef strips to the onion mixture and cook on medium heat until meat is cooked through. Lower temperature and add broccoli until heated thru. Serve immediately over hot rice.
Alternate: Marinate meat in soy sauce, onions, garlic, and ginger for 2 hours before cooking and then add to soy sauce, orange juice and brown sugar.