One of my son's favorites, I'm finally getting around to writing it down so he can make it, himself. It's important to choose a nice cut of beef, because the beef is essentially stir-fried, rather than slow cooked. I like to use brown cremini mushrooms in this, but button mushrooms will also work just fine. It's important to use low-sodium broth, to prevent the finished sauce from becoming too salty. Serve over noodles or rice.