Season beef with salt, pepper, and garlic powder and fry in a little oil of your choice. Only takes a minute or so on each side. Remove from pan and set aside. Put the soy sauce, water and brown sugar in a sauce pan and bring to a boil, reduce the heat a bit. Make your cornstarch slurry and add to the soy sauce mixture until it's thickened to your liking. Add the green onion to the sauce cook for a minute longer then add the meat to warm it through. Serve over cooked white rice and enjoy! If you like it a little spicy add some crushed red pepper. These measurements are approximate, just play with it until you get the taste you like.