Slice the beef flank steak into thin strips against the grain. In a bowl, combine the beef, baking soda, light soy sauce, peanut oil, and cornstarch. Let it marinate for 15 minutes.

In a separate bowl, whisk together chicken broth, oyster sauce, light soy sauce, dark soy sauce, sugar, cornstarch, and sesame oil until smooth. Set aside.

Heat a skillet over medium-high heat, add peanut oil, then sear the marinated beef in a single layer for 1 minute without stirring, flip, and cook for another minute until golden brown. Set aside.

In the same skillet, add remaining oil, onion, garlic, and ginger. Stir-fry for about 2 minutes until the onion is translucent.

Add asparagus (or seasonal veggies) to the skillet and stir frequently for 1 minute until just tender.

Pour the prepared sauce into the skillet with the beef and vegetables. Stir constantly for 1-2 minutes until the sauce thickens.

Serve hot on a plate, spooning sauce over the dish. Enjoy it immediately with steamed rice or noodles.