Begin by slicing the flank steak against the grain into thin strips. In a bowl, combine the steak with soy sauce, peanut oil, and cornstarch, ensuring an even coating. Let the beef marinate for about 10 minutes.

In a separate bowl, mix together the chicken stock, Shaoxing wine, dark and regular soy sauces, brown sugar, and a bit of cornstarch. Set the sauce aside.

Bring water to a boil in a large skillet and add the broccoli florets. Cover and steam for about 1 minute until bright green. Drain and set aside.

In the same skillet, heat a tablespoon of oil over medium-high heat. Add the marinated beef and sear for about 2-3 minutes until lightly browned.

Stir in minced garlic and ginger and sauté for about 30 seconds until fragrant.

Return the steamed broccoli to the skillet, then pour the prepared sauce over everything. Stir together and cook for an additional minute until the sauce thickens.

Transfer the dish to a serving plate and serve hot over rice.