Crispy Mongolian Beef in 15 Minutes Step-by-step instructions

Before you start

Before cooking, slice the flank steak against the grain into thin strips and toss with cornstarch. Whisk together the soy sauce, brown sugar, ginger, and garlic in a small bowl.

Cut the scallions into 2-inch batons. Set up a wire rack over a baking sheet near the stove for draining the fried beef. Have all ingredients within reach, as the cooking process moves quickly.

Instructions

Prep and Heat

1. 1Prep the Steak and Glaze
   Slice the flank steak thinly against the grain into 1/4-inch strips. Place the strips in a large bowl and toss with the cornstarch until each piece is evenly coated. In a separate small bowl, whisk together the soy sauce, brown sugar, ginger, and garlic until the sugar is mostly dissolved and the glaze is smooth.
   Look for The steak is fully coated in a dry, powdery layer of cornstarch; the glaze is dark and syrupy.
   Tip Pat the steak dry before slicing to help the cornstarch adhere better.
2. 2Heat the Frying Oil
   Pour the vegetable oil into a wok or large heavy skillet. Heat over high heat until the oil reaches 385°F (196°C) on a deep-fry thermometer. While the oil heats, set a wire rack over a baking sheet near the stove for draining the fried beef.
   Look for The oil shimmers and a small piece of cornstarch sizzles immediately when dropped in.
   Tip Use a thermometer for accuracy; if the oil is too cool, the coating won't crisp.

The steak is sliced and coated in a dry, powdery cornstarch layer. The glaze is whisked and smooth, with the sugar mostly dissolved. The oil is shimmering and reads 385°F on the thermometer. Everything is ready for the fast cooking that follows.

Fry and Toss

3. 3Flash-Fry the Beef
   Working in batches, add the coated steak strips to the hot oil in a single layer. Fry for 90 seconds, turning once, until the edges are golden brown and crispy. Use tongs to transfer the beef to the wire rack. Repeat with the remaining beef, allowing the oil to return to 385°F (196°C) between batches. Let it rest for 3 minutes before slicing.
   Look for The beef is deep golden brown with crispy, craggy edges; it sizzles as it drains.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Do not overcrowd the wok—fry in small batches to keep the oil temperature steady.
4. 4Wok-Toss with Glaze and Scallions
   Carefully pour out the frying oil, leaving about 1 tablespoon in the wok. Return the wok to high heat and add the glaze. Let it bubble for about 30 seconds, then add the fried beef and scallion batons. Toss everything vigorously for 45 seconds until the beef is evenly coated and the scallions are slightly charred. Let it rest for 3 minutes before slicing.
   Look for The glaze turns thick and glossy, clinging to the beef; the scallions soften and char slightly.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Keep the heat high to reduce the glaze quickly—this creates the sticky coating.

The fried beef is deep golden brown with crispy, craggy edges. The glaze bubbles and thickens in the wok, turning glossy. The scallions soften and char slightly as they are tossed with the beef. The kitchen smells of sweet soy and ginger—the dish is nearly done.

Rest and Serve

5. 5Finish and Serve
   Remove the wok from the heat. Transfer the Mongolian beef to a serving platter. Let it rest for 3 minutes before serving so the beef stays juicy. Serve hot, with extra scallions if desired.
   Look for The beef is glossy with a dark, caramelized glaze and the scallions are bright green.
   Safe temperature 145°F (63°C) internal temperature (steaks, chops and roasts)
   Tip Resting allows the juices to redistribute—don't skip it for the most tender bites.

The beef is coated in a dark, glossy glaze that clings to every piece. The scallions are bright green with charred tips. After a 3-minute rest, the beef is juicy and tender inside, with a satisfying crunch on the outside. Ready to serve immediately.

Common mistakes

One common mistake is overcrowding the wok during frying, which lowers the oil temperature and results in soggy, greasy beef. Always fry in small batches and allow the oil to return to 385°F between batches.

Another pitfall is overcooking the glaze—it can become too thick or burn if left on high heat too long. Toss the beef and scallions quickly, just until coated, then remove from heat immediately.

How to tell it’s done

The beef is done when it reaches an internal temperature of 145°F (63°C) for medium-rare, but since it's sliced thin and flash-fried, it will likely be well past that.

The coating should be deep golden brown and crispy, and the glaze should be thick and glossy, coating each piece evenly.

The scallions should be slightly charred but still bright green. Let the beef rest for 3 minutes before serving to allow the juices to settle.

• Steaks, chops and roasts: 145°F (63°C) in the thickest part, then a 3-minute rest