Julian,
I used top sirloin, since it was on sale at my market, cheaper than round steak, cut thinly into 3" long strips. I mixed a couple of tablespoons of cornstarch, a tablespoon or so of water and about a half teaspoon of garlic powder, then tossed the steak to coat. I stir fried the steak in about a tablespoon of oil until it was medium-rare to medium, then took it out and set it aside. I stir fried about a half-pound (4 cups or so) of broccoli florets and a quarter of a large Vidalia onion cut pole-to-pole in another tablespoon of oil and when the broccoli was still a bit crisp, added a mixture of a tablespoon of cornstarch, a third cup of soy sauce, two tablespoons of brown sugar, a half-teaspoon of ground ginger and a half cup of water. I let it thicken, then added the beef back.
I'm sorry I didn't take pictures, maybe next time.
Rick