B4. Mongolian Beef, Spicy Recipe

Slice and marinate

Freeze flank steak for 20–30 minutes until slightly firm to make thin slicing easier. Slice across the grain into 1/8–1/4-inch thin strips. Place slices in a bowl, add 2 tbs soy sauce and toss to coat. Let sit 10 minutes while you prepare other ingredients.

Coat beef

Place 1 cup cornstarch in a shallow dish or bowl. Dredge each slice of steak in cornstarch, shaking off excess. Arrange on a tray in a single layer.

Heat 1 cup vegetable oil in a large heavy skillet or wok over medium-high heat until shimmering (approximately 350°F if using a thermometer). Fry the cornstarch-coated beef in batches — do not overcrowd — 1–2 minutes per side until crisp and browned. Use a slotted spoon to transfer cooked beef to a paper towel–lined plate to drain. Reserve oil for later or discard 2–3 tbs and keep 2 tbs in the pan for sauce step.

In a bowl, whisk together 1 cup low-sodium soy sauce, 1 cup water, 2 tbs brown sugar, 1 tbs dark brown sugar (if using), 1 tsp rice vinegar, 1 tsp hoisin sauce, and 1 tsp sesame oil until sugar mostly dissolves.

In a small cup, stir 1 tbs cornstarch into 2 tbs cold water to make a slurry; set aside.

Heat 2 tbs neutral oil in a clean wok or large skillet over medium-high heat. Add the ginger and garlic and stir-fry 30–45 seconds until fragrant but not browned.

Add 1 tsp dried red chili flakes (and the optional sliced fresh red chili if using) and stir 10–15 seconds to bloom the chile heat.

Carefully pour in the prepared sauce mixture. Bring to a simmer and cook 2–3 minutes to meld flavors.

Stir slurry and slowly whisk into the simmering sauce. Continue to simmer 1–2 minutes until the sauce thickens to a glossy consistency that will coat the beef. Taste and adjust heat or sweetness as needed (add a pinch more sugar or a splash of soy).

Return the fried beef to the wok and toss quickly to coat evenly with the sauce. Stir in the scallion pieces and toss 30–45 seconds—scallions should be bright and slightly softened but still have bite.

If the sauce becomes too thick, add 1–2 tbs hot water to loosen. If too thin, simmer a little longer until it reaches desired thickness.

Remove from heat. Sprinkle toasted sesame seeds and extra sliced scallion greens over the top.

Serve immediately over steamed white rice or fried rice. Provide extra chili flakes at the table for additional heat.