This is a Chinese-American stir-fry: thin slices of flank steak coated in cornstarch, seared fast, then tossed in a soy-ginger-brown sugar sauce that thickens in minutes. The honest reason to make it tonight is that the whole thing — prep included — is done in 30 minutes, and the ingredients are already in most pantries.
The technique that matters
Two things drive this dish. First, slice the flank steak against the grain and keep the strips thin — about ¼ inch. Cut with the grain and the meat turns chewy no matter how carefully you cook it. Second, sear in batches. Crowding the pan drops the temperature and the beef steams instead of browns, which means you lose the crust that gives the sauce something to cling to. Work in two batches, give each piece 1–2 minutes per side without moving it, and the cornstarch coating will do the rest — it browns on contact and later thickens the sauce automatically when the beef goes back in.
What can go wrong
- Sauce turns grainy or crystallizes: This happens when the heat is too low and the brown sugar doesn’t fully dissolve before you add the beef back. Keep the heat at medium-high and stir constantly for the full 2–3 minutes until the sauce is visibly glossy.
- Beef releases water and the sauce won’t thicken: Pat the sliced steak dry with paper towels before tossing in cornstarch. Surface moisture prevents browning and dilutes the sauce.
- Cornstarch coating falls off during searing: Let the coated beef rest on a plate for 2–3 minutes before it hits the pan. The coating bonds to the meat and holds better with a short rest.
- Sauce reduces too fast and burns: Flank steak is lean and the sugar in this sauce scorches quickly over very high heat. If the sauce starts darkening too fast in the final combine step, pull the pan off the burner for 20 seconds and stir — it will recover.
- Finished dish tastes flat: Low-sodium soy sauce is recommended in the recipe, but brands vary significantly in saltiness. Taste the sauce before adding the beef back and adjust — a small splash of regular soy sauce or a pinch of salt fixes it in seconds.
Make-ahead notes
Leftovers keep in an airtight container in the fridge for up to 3 days. The sauce thickens considerably as it sits, so add a tablespoon or two of water when reheating in a skillet over medium heat — it loosens back to the right consistency in about 2 minutes. Skip the microwave if you can; it toughens the beef. For freezing, portion cooled leftovers into freezer bags, press flat, and freeze for up to 2 months. Thaw overnight in the fridge before reheating on the stovetop. Skip the garnish on anything you’re storing — not worth the extra dish, and green onions don’t survive the fridge well anyway.
Mongolian Beef
Equipment
- Large skillet or wok
- Mixing bowls
- Chefs Knife
- Measuring cups and spoons
Ingredients
Main Ingredients
- 1 lb beef flank steak sliced thin against the grain
- ¼ cup cornstarch
- â…“ cup soy sauce low sodium preferred
- â…“ cup water
- ½ cup brown sugar packed
- 3 tbsp vegetable oil divided
- 2 cloves garlic minced
- 1 tbsp fresh ginger grated
- 2 pcs green onions sliced, for garnish
- 1 pinch salt to taste
- 1 pinch ground black pepper to taste
Optional Garnish and Serving
- 2 cups steamed rice for serving
Instructions
- Prepare the Beef: Thinly slice the flank steak against the grain into bite-sized strips.
- Coat and Sear the Beef: Toss the beef strips with cornstarch until evenly coated. Heat 2 tablespoons of vegetable oil in a large skillet or wok over medium-high heat (190°C/375°F) until shimmering. Sear the beef in batches to avoid overcrowding, cooking each side for about 1-2 minutes until browned. Remove and set aside.
- Make the Sauce: In the same skillet, add the remaining tablespoon of oil. Sauté the garlic and ginger until fragrant, about 30 seconds. Add soy sauce, water, and brown sugar, stirring until the sugar dissolves and the sauce slightly thickens, about 2-3 minutes.
- Combine Beef and Sauce: Return the beef to the skillet, stirring to coat all pieces evenly with the sauce. Cook for an additional 1-2 minutes, allowing flavors to meld. Adjust seasoning with salt and pepper as desired.
- Garnish and Serve: Transfer the Mongolian Beef to a serving dish, garnishing with sliced green onions. Serve hot over a bed of steamed rice.
Notes
- For a deeper flavor, marinate the beef briefly in the soy sauce mixture before cooking.
- Substitute tamari for soy sauce for a gluten-free version.
- The dish pairs well with a light, floral white wine or jasmine tea.
Nutrition
FAQ
Can I use a different cut of beef instead of flank steak?
Yes — skirt steak works just as well and is often cheaper. Sirloin sliced thin is a solid backup too, though it’s slightly less forgiving if you accidentally overcook it.
Do I need a wok, or will a regular skillet work?
A large skillet works fine. The key is that the pan is wide enough to sear the beef in a single layer per batch — a 12-inch skillet handles this recipe without crowding.
Can I double the recipe for a larger group?
You can double the sauce and ingredients, but still cook the beef in the same small batches — don’t try to sear twice the meat at once. Plan for an extra 8–10 minutes of total cook time to get through all the batches.
What to cook next
- Sizzling Skillet Steak Fajitas
- Quick Ginger Scallion Wontons
- Quick Korean Bibimbap Bowls
- Spicy Korean Rice Cakes