Step by step

Method

4 steps

1. 1

   Pat 1½ lb flank steak dry and slice thin against the grain (about ⅛-inch). Toss with ¼ cup cornstarch until every piece looks lightly dusty, then rest 10 minutes — the starch fries into a thin crust and later thickens the sauce.

2. 2

   Whisk ½ cup low-sodium soy sauce, ⅓ cup brown sugar, ⅓ cup water, and 1 teaspoon sesame oil until the sugar mostly dissolves. Cut 4 green onions into 2-inch pieces; mince 4 garlic cloves and grate 1 teaspoon ginger.

3. 3

   Heat 2 tablespoons oil in a wide skillet over high until it shimmers. Sear the steak in a single layer in batches, 45–60 seconds per side, until the edges brown and the cornstarch looks set — don't crowd or it'll steam gray. Set aside.

4. 4

   Add the remaining 1 tablespoon oil, then garlic and ginger for 30 seconds until fragrant (not burnt). Pour in the sauce and simmer 1–2 minutes until it looks glossy and lightly syrupy. Return the beef and green onions; toss 1–2 minutes until everything is coated and the onions soften just at the edges. Serve over hot rice. You want tender, sticky-sweet beef with a shiny sauce that clings — not a watery soy puddle or tough chewy strips.