Easy Mongolian Beef
This easy Mongolian beef recipe brings restaurant-quality stir-fry right to your kitchen in under 30 minutes. Tender slices of beef are coated in a glossy sauce made with soy, brown sugar, garlic, and ginger, then served over fluffy rice for a satisfying weeknight dinner that beats delivery every time.
Equipment
- Chef's knife - Sharp for slicing beef thinly
- Cutting board
- Large skillet or wok - 12-inch works best
- Medium mixing bowl - For coating the beef
- Small bowl - For mixing the sauce
- Tongs or spatula - For flipping the beef
- Measuring cups and spoons
Ingredients
- 1 1/2 pounds flank steak - 680g, sliced thinly against the grain
- 1/4 cup cornstarch - 32g, for coating the beef
- 3 tablespoons vegetable oil - or any neutral oil, divided
- 1 teaspoon sesame oil
- 5 cloves garlic - minced
- 1 tablespoon fresh ginger - minced or grated
- 1/2 cup low-sodium soy sauce - 120ml
- 1/2 cup brown sugar - 100g, packed
- 1/4 cup water - 60ml
- 1/4 teaspoon red pepper flakes - optional, for heat
- 3 green onions - sliced, white and green parts separated
For Serving
- Steamed white rice - for serving
- Toasted sesame seeds - optional, for garnish
Instructions
- Place flank steak in the freezer for 20-30 minutes to firm up. Slice across the grain into 1/4-inch thick strips, then cut into 2-3 inch pieces. Pat dry with paper towels.
- Add sliced beef to a large bowl and sprinkle with cornstarch. Toss thoroughly to coat each piece evenly, then shake off any excess. Let sit for 5 minutes.
- In a small bowl, whisk together soy sauce, brown sugar, water, minced ginger, and half the minced garlic until the sugar dissolves completely.
- Heat 2 tablespoons vegetable oil in a large skillet over medium-high heat. Working in batches, add beef in a single layer and cook undisturbed for 1-2 minutes until golden and crispy. Flip and cook 1 minute more. Transfer to a plate and repeat with remaining beef.
- Reduce heat to medium and add remaining 1 tablespoon oil. Add remaining garlic and white parts of green onions, cook 30-40 seconds until fragrant. Pour in sauce, scraping up browned bits, and add sesame oil and red pepper flakes. Bring to a boil and let it thicken for 2-3 minutes.
- Return all seared beef to the skillet and toss gently to coat with sauce. Cook 1-2 minutes until heated through and sauce clings to the beef. Remove from heat, stir in most of the green onion tops, and garnish with reserved green onions. Serve immediately over rice.
Notes
- Freeze the beef briefly: Putting flank steak in the freezer for 20-30 minutes makes it much easier to slice thinly and evenly, resulting in more tender pieces.
- Slice against the grain: Always cut perpendicular to the muscle fibers to shorten them, which makes each bite significantly more tender and easier to chew.
- Don't skip the cornstarch coating: This creates a protective barrier that keeps the beef tender while creating crispy edges, and it helps the sauce cling to each piece beautifully.
- Use high heat: A hot pan is essential for achieving that crispy sear on the beef without overcooking the interior. Make sure your oil is shimmering before adding the beef.
- Cook in batches: Overcrowding the pan lowers the temperature and causes steaming instead of searing, resulting in gray, tough beef instead of caramelized pieces.
- Don't overcook: Flank steak becomes tough when overcooked, so aim for medium-rare to medium for the most tender results.
- Adjust sweetness: If you prefer less sweet, reduce the brown sugar to 1/3 cup and add an extra tablespoon of soy sauce for more savory depth.
- Storage: Store cooled Mongolian beef in an airtight container in the refrigerator for up to 4 days. Reheat on the stovetop with a splash of water or broth to loosen the sauce.
- Make it spicier: Double the red pepper flakes or add 1-2 teaspoons of sriracha or sambal oelek to the sauce for serious heat.
- Vegetable variation: Stir in sliced bell peppers, snap peas, or sliced onions along with the white parts of the green onions for more color and nutrition.