Begin by slicing the flank steak against the grain into thin strips. In a mixing bowl, combine the beef with soy sauce, peanut oil, and cornstarch. Allow to marinate for 10 minutes.

In another bowl, whisk together chicken or beef stock, Shaoxing wine, dark soy sauce, and brown sugar to prepare your stir-fry sauce; set aside.

Bring a few inches of water to a boil in a skillet and steam the broccoli for about 1 minute until vibrant green and tender but still crisp; set aside.

Heat peanut oil in the same skillet over medium-high heat. Add the marinated beef in a single layer and sear for about 30 seconds until browned.

Stir in minced garlic and ginger, sautéing for about 30 seconds until fragrant. This infuses the dish with warm flavors.

Return steamed broccoli to the skillet. Pour in the sauce and stir to combine everything. Cook for an additional minute until the sauce thickens.