Mongolian Beef Recipe

Slice and marinate

Freeze flank steak for 20–30 minutes to firm slightly, then slice thinly (1/8–1/4 inch) across the grain. Place slices in a bowl and add 1 tablespoon soy sauce, 2 tablespoons cornstarch and optionally 1/2 teaspoon baking soda. Toss to coat evenly. Let sit 10–15 minutes while you prepare other components.

After marinating, shake off any excess cornstarch (do not rinse). The coating should be light but even to help achieve a glossy, slightly crisp exterior when cooked.

Mix the sauce

In a bowl or measuring cup, whisk together 1/2 cup low-sodium soy sauce, 1/4 cup water, 1/2 cup packed light brown sugar, 1 teaspoon hoisin sauce, 1 teaspoon rice vinegar and 1 teaspoon sesame oil until sugar mostly dissolves. In a small separate bowl, mix 1 teaspoon cornstarch with 1 tablespoon cold water to make a thin slurry; set both aside.

Prepare aromatics: peel and finely mince 1 tablespoon ginger and mince 3 cloves garlic. Trim and slice 4 scallions: separate white parts from green tops; slice whites thinly and cut greens into 1–2 inch pieces for finishing.

Heat a large heavy skillet or wok over medium-high to high heat until very hot. Add 2 tablespoons neutral oil and swirl to coat.

Working in a single layer, sear the marinated beef in batches (do not overcrowd) for 45–60 seconds per side until just browned and mostly cooked through. Remove each batch to a plate. If desired, add additional 1 tablespoon oil between batches.

Reduce heat to medium. If the pan is dry, add a small splash (about 1 tablespoon) of oil. Add minced ginger, minced garlic and 1/4 teaspoon dried chili flakes (if using). Stir-fry briefly 20–30 seconds until aromatic—do not burn.

Pour the prepared sauce into the pan and bring to a gentle simmer, scraping up any browned bits from the bottom of the pan with a wooden spoon. Let simmer 1–2 minutes to combine flavors.

Whisk the cornstarch slurry again and pour into the simmering sauce while stirring constantly. Cook 30–60 seconds until sauce thickens to a glossy coating—remove from heat if it becomes too thick.

Return all cooked beef (and any accumulated juices on the plate) to the skillet and toss quickly to coat with the sauce. Add the white parts of the scallions and continue tossing 30–60 seconds to heat through and allow scallion whites to soften slightly.

Stir in the scallion greens, toasted sesame seeds and 1/4 teaspoon freshly ground black pepper. Give a final toss and transfer to a serving platter immediately.