Mongolian beef is one of those takeout classics that sounds fancy but is secretly one of the easiest things you can make at home. Tender, crispy-edged flank steak coated in a glossy, sweet-savory sauce made from soy, brown sugar, garlic, and ginger — then piled on top of rice with fresh green onions. It’s better than your favorite restaurant version and takes about 35 minutes from start to finish.
The trick to nailing this dish at home is all in the prep: dust the steak in cornstarch before frying, which creates that irresistible slightly crispy coating that soaks up all that luscious sauce. Don’t skip that step. Once you bite into a piece of crispy-edged beef swimming in that deep, complex sauce, you’ll completely understand why this dish has such a devoted fan base.
Why You'll Love This Recipe
- Better than takeout — and ready in 35 minutes.
- The cornstarch coating creates a crispy-yet-tender beef texture that’s genuinely addictive.
- The sauce is sweet, savory, garlicky, and deeply satisfying.
- Naturally pairs with anything — rice, noodles, or even quinoa.
- Impressively restaurant-quality for a weeknight dinner.
- The bright green spring onions add freshness and color to the finished dish.
Ingredients
Main Ingredients
- 1 pound beef flank steak, sliced ¼-inch thick on the diagonal
- ¼ cup cornstarch
- 1 cup vegetable oil (for frying) + 2 teaspoons for sauce
- 1 tablespoon finely chopped garlic
- ½ teaspoon grated fresh ginger root
- ⅔ cup dark brown sugar
- ½ cup soy sauce
- ½ cup water
- 2 bunches green onions (spring onions), cut into 2-inch lengths
Optional Add-ins
- Sesame seeds (for garnish)
- Red pepper flakes (for heat)
- A splash of rice vinegar in the sauce (for brightness)
- Baby bok choy, wilted alongside the beef
- Cooked lo mein noodles instead of rice
Step-by-Step Instructions
- Slice the flank steak across the grain into thin strips, about ¼ inch thick. Toss the strips in the cornstarch until evenly coated. Set aside.
- Make the sauce: heat 2 teaspoons of vegetable oil in a small saucepan over medium heat. Add the garlic and ginger, stirring for 30 seconds. Pour in the soy sauce, brown sugar, and water. Stir to dissolve the sugar and bring to a brief simmer. Set sauce aside.
- In a large skillet or wok, heat the remaining 1 cup of oil over medium-high heat until it shimmers. Working in batches, fry the cornstarch-coated beef strips for 2–3 minutes until golden and crisp on the edges. Remove with a slotted spoon and drain on paper towels.
- Pour off all but 1 tablespoon of oil from the skillet. Return the skillet to medium heat and add the fried beef. Pour the prepared sauce over the beef and toss to coat.
- Add the spring onions and toss everything together. Bring to a brief boil and cook for 1–2 minutes until the onions are bright green and just softened.
- Serve immediately over steamed jasmine rice, garnished with sesame seeds if desired.
Pro Tips
- Freeze the flank steak for 20 minutes before slicing for easier, more precise cuts.
- Pat the beef dry before tossing in cornstarch — moisture is the enemy of crispiness.
- Don’t crowd the pan when frying; work in small batches for maximum golden crust.
- The sauce comes together fast — have it ready before you start frying the beef.
- Dark brown sugar gives the sauce a deeper, more complex molasses flavor vs. light brown sugar.
Variations & Substitutions
Use chicken breast or thighs instead of flank steak. Broccoli, snap peas, or baby bok choy are excellent vegetable additions — toss them into the pan with the onions. For a lighter version, bake the cornstarch-coated beef on a wire rack at 400°F for 15 minutes instead of frying. Swap brown sugar for honey for a different sweetness profile.
What to Serve With
Jasmine rice is the classic base. Steamed or stir-fried bok choy on the side is gorgeous. This dish also works wonderfully over lo mein noodles or with a drizzle of chili oil for heat lovers.
Storage & Reheating
Store leftovers in the fridge for up to 3 days. Note that the beef will lose its crispiness — that’s normal. Reheat in a hot skillet or wok for best results. Not ideal for freezing, as the sauce can separate.
Recipe Card
Prep Time: 15 minutes | Cook Time: 20 minutes | Total Time: 35 minutes | Servings: 4
Ingredients (Summary):
1 lb flank steak sliced thin, ¼ cup cornstarch, 1 cup oil, 1 tbsp garlic, ½ tsp ginger, ⅔ cup dark brown sugar, ½ cup soy sauce, ½ cup water, 2 bunches green onions
Instructions (Summary):
Coat beef in cornstarch. Make sauce with garlic, ginger, soy, sugar, water. Fry beef in batches until crispy. Drain oil, return beef to pan. Add sauce and spring onions, toss 1–2 min. Serve over rice.
Closing Thoughts
This Mongolian beef recipe is genuinely one of the most rewarding 35-minute dinners you can make. Try it once and I promise it’ll be on permanent rotation. Tell me in the comments if you added any extra vegetables — and whether you served it over rice or noodles!