In a large bowl, combine thinly sliced beef flank steak with baking soda, soy sauce, peanut oil, and cornstarch. Let it marinate for about 15 minutes.

In a small bowl, whisk together chicken broth, oyster sauce, light and dark soy sauces, sugar, cornstarch, and sesame oil until fully dissolved. Set aside.

Heat peanut oil in a skillet over medium-high heat. Add marinated beef, sear undisturbed for 1 minute, flip, and cook for an additional minute until browned.

Add sliced onions, minced garlic, and grated ginger to the same skillet. Stir-fry for about 2 minutes until fragrant and onions are translucent.

Add asparagus pieces and stir-fry for 1 minute until they start to soften but remain vibrant.

Pour the sauce mixture into the skillet and cook until thickened, about 2 minutes. Return beef to skillet and toss to coat.