Slice the flank steak against the grain into thin strips and marinate with soy sauce, peanut oil, cornstarch, and baking soda. Let marinate for 10 minutes.

In a separate bowl, whisk together chicken stock, Shaoxing wine, dark soy sauce, and brown sugar. Set aside.

Steam broccoli in boiling water for about 1 minute until vibrant, then remove and set aside.

Heat peanut oil in the skillet and add the marinated beef, searing for about 30 seconds on one side before flipping to cook for 1-2 minutes total.

Add minced garlic and ginger to the skillet, stirring for about 30 seconds until fragrant.

Combine steamed broccoli with the beef and pour the sauce over it, stirring until the sauce thickens for about 1 minute.