Instructions

• Place 1 ½–2 pounds flank steak (sliced into ¼-inch thick strips) and ⅓ cup cornstarch into a large zip-top bag. Seal the bag and shake vigorously until the beef is evenly coated. Let the coated beef rest in the bag for about 15 minutes.
• Heat a large skillet over medium-high heat. Add 1 tablespoon of the 2 tablespoons vegetable oil and heat until shimmering.
• Add half of the coated beef in a single layer (do not overcrowd). Cook undisturbed 3–4 minutes, then flip and cook another 3–4 minutes until browned. Transfer the cooked beef to a plate.
• Add the remaining 1 tablespoon vegetable oil to the skillet, heat until shimmering, then add the remaining half of the coated beef and cook the same way: 3–4 minutes per side until browned. Transfer that beef to the plate with the first batch.
• Reduce heat to medium. Add ½ teaspoon sesame oil to the skillet, then add 2 teaspoons minced garlic and 1 teaspoon minced fresh ginger. Cook, stirring, about 1 minute until fragrant.
• In a medium bowl, whisk together ½ cup low-sodium soy sauce, ⅓ cup lightly packed light brown sugar, ⅓ cup water, and 1 tablespoon rice vinegar. Pour the sauce into the skillet and cook, stirring, until the brown sugar is completely dissolved, about 2–3 minutes.
• In a small bowl, mix 1 tablespoon cornstarch with 2 tablespoons water to make a slurry. Stir the slurry into the sauce, then reduce heat to medium-low and simmer 1–2 minutes, stirring, until the sauce thickens.
• Return all the cooked beef to the skillet and stir to coat thoroughly with the sauce. Cook 1–2 minutes more until the beef is heated through.
• Remove from heat and serve immediately.