With little fat and usually no bone, sirloin steak is one of the easiest meats to prepare for stir fry. Easy preparation, however, does not equate to no preparation. Taking certain steps prior to stir frying sirloin steak can make the difference between steak that is tender and flavorful and steak that is tough or mushy.
Set the meat in your freezer for about 30 minutes or until it just starts to freeze. Frosty meat is easier to control when slicing.
Trim off any visible fat from the edges of the steak. If there is a bone, cut to separate the meat from the bone. A straight-edge knife is appropriate for both tasks, although if you have a boning knife, using it can make separating meat from the bone easier.
Inspect the meat to see the direction of the grain, or the direction in which the meat fibers run. Position a very sharp straight-edge or chef’s knife at a 45-degree angle to the grain and cut it into no more than 1/4-inch-thick slices. Thin, bias-cut slices that follow the grain are essential for tender stir-fry meat.
Cut each slice into bite size strips about 3 inches in length.
Scoop up the meat strips using a spatula and place them in a glass bowl or plastic food bag.
Combine marinade ingredients in a small mixing bowl. Sirloin steak is a naturally tender cut of beef, so choose marinade ingredients with an eye toward seasoning rather than tenderizing the meat. Ingredients such as olive oil, low-sodium soy sauce or teriyaki sauce, honey and a sprinkling of black pepper help season the meat. In contrast, ingredients such as citrus juice, wine or vinegar, ginger and pineapple break down protein and muscle fibers. Although timing can temper their effects, limit these ingredients to preserve the texture and natural tenderness of your steak.
Pour the marinade into the bowl or bag containing the sirloin steak strips. If you use a bowl, stir to coat the meat, then cover and set in your refrigerator. If you use a food bag, seal the bag and them massage it with your hands to coat the meat strips before placing in your refrigerator. Marinate the meat for 30 minutes to no more than four hours, stirring or massaging the bag several times to ensure the meat marinates evenly.
Remove the meat using a slotted spoon and discard the used marinade. Your sirloin steak is now ready for frying.