Your goal when stir-frying beef is to have uniform size pieces to ensure even cooking. You may save time by purchasing packages of pre-cut beef, but it may more economical to slice your own. Almost any tender beef cut, such as sirloin, top sirloin, tri-tip, ribeye, top loin or tenderloin may be trimmed and cut into the appropriate size strips for use in beef stir-fry recipes. Even some less tender cuts, such as flank, top round and round tip steaks, are suitable for stir-frying. Remember this cook’s tip, too: Place meat in freezer for thirty minutes and it will be easier to cut into thin slices.
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