A great homemade beef stir-fry is all about technique, from prepping the ingredients to finishing the dish in the pan. Flank steak and sirloin are good cuts for stir-frying. They should be sliced against the grain diagonally; slice thinly, so they’ll cook fairly quickly (don’t aim for razor thin, though, or you’re likely to overcook). Freezing the meat for 20 to 30 minutes makes slicing easier.
Next comes velveting, a key step in achieving tender results: Toss the sliced beef with a mixture of cornstarch, xiaoxing rice wine or dry sherry, and soy sauce (scoopG suggests a ratio of 3 tablespoons cornstarch, 2 teaspoons rice wine or sherry, and 1/2 teaspoon soy per 1/2 pound of meat), and marinate for 10 to 30 minutes. Alternately, simply toss the beef with some cornstarch, shaking off the excess before cooking. The cornstarch coating prevents the meat from cooking up tough when it hits a very hot pan. This method works wonderfully with pork and chicken, as well.
When it’s time to cook, get your pan as hot as possible. Most home stoves can heat a cast iron or stainless steel skillet hotter than a wok, say some hounds, so they prefer these for stir-fries. Add some oil and your meat; do not try to cook too much at once, or you’ll bring down the heat in your pan substantially.
Stir-fry and remove the beef before it is fully cooked through. Wipe out your pan, add more oil, stir-fry aromatics and vegetables, then return the beef to the pan at the last minute, right before you add any sauce ingredients for a final toss. This last minute or two of cooking will pull the whole thing together and give you beef that’s tender and not overdone.
Board Link: Any tips for stir-frying beef (and other meats)?