Speedy Korean Beef and Broccoli Stir-Fry

In a medium bowl, combine the sliced flank steak with 1 tablespoon soy sauce, 1 teaspoon sesame oil, and 1 tablespoon cornstarch. Toss to coat evenly and let marinate for at least 10 minutes.

In a small bowl, whisk together 1/4 cup soy sauce, brown sugar, rice vinegar, 1 teaspoon sesame oil, and red pepper flakes (if using) to create the stir-fry sauce. Set aside.

Heat 1 tablespoon of vegetable oil in a large skillet or wok over medium-high heat until shimmering. Add the broccoli florets and stir-fry for 3-4 minutes until tender-crisp. Remove the broccoli from the skillet and set aside.

Add the remaining 1 tablespoon of vegetable oil to the skillet. Add the marinated beef in a single layer and cook for 2-3 minutes per side, until browned and cooked through. You may need to do this in batches to avoid overcrowding the pan.

Reduce the heat to medium. Add the minced garlic and grated ginger to the skillet and cook for 30 seconds until fragrant.

Pour the prepared stir-fry sauce into the skillet and bring to a gentle simmer, stirring constantly, for 1 minute until slightly thickened.

Return the cooked broccoli and beef to the skillet. Toss everything together to coat evenly with the sauce. Cook for 1-2 minutes more, ensuring everything is heated through.

Serve immediately over steamed rice or noodles.