Slice the flank steak into thin strips and combine it in a bowl with Shaoxing wine, cornstarch, and a pinch of salt. Mix well to coat the beef evenly and let it marinate for about 15 minutes.

In a separate bowl, whisk together low-sodium beef broth, soy sauce, oyster sauce, remaining Shaoxing wine, cornstarch, sugar, Chinkiang vinegar, and white pepper. Mix until the ingredients are well combined and the cornstarch is dissolved.

Cook the Hong Kong pan fry noodles according to the package instructions for about 2-3 minutes until tender. Drain and rinse under cold water.

In a large skillet, heat peanut oil over medium-high heat. Add the drained noodles, pressing them down to form a patty. Cook undisturbed for about 4-5 minutes or until golden brown and crispy. Flip and fry the other side for another 4-5 minutes.

In the same skillet, add more peanut oil, then pour in the marinated beef. Cook for about 3-4 minutes until browned. Transfer to a plate, leaving the juices in the pan.

Add more peanut oil if necessary, then toss in sliced onions and carrots. Sauté for about 2-3 minutes until softened, then add ginger, garlic, and baby bok choy. Cook for another 2-3 minutes.

Pour the prepared sauce into the skillet, stirring it into the vegetables. Cook for about 2-3 minutes until the sauce thickens slightly. Return the cooked beef, mixing everything.

Pour the beef and vegetable mixture over the crispy noodles on the serving plate. Garnish with optional sesame seeds or green onions and serve immediately.