FOR THE VEGETABLE STIR FRY:
Marinate the steak: In a medium bowl, toss the sliced steak with cornstarch, dark soy sauce, baking soda, white pepper, and salt. Set aside.
Prepare the sauce: In another bowl or measuring cup, whisk beef broth, low sodium soy sauce, brown sugar, oyster sauce, rice vinegar, dark soy sauce, cornstarch, white pepper, and cayenne powder together until smooth. Set aside.
Cook the broccoli: Heat 1 tablespoon neutral oil in a large pan or wok over medium heat. Add broccoli and stir-fry briefly. Add a splash of water, cover, and steam for 2-3 minutes until broccoli is tender-crisp. Remove broccoli and set aside.
Cook the steak: Over medium-high heat, heat the wok or pan until it’s very hot, then add 1 1/2 to 2 tablespoons neutral oil. Add the marinated steak and stir-fry until just cooked through and seared, about 2-3 minutes. Remove and set aside.
Sauté aromatics: Lower the heat to medium-low. Add sesame oil and 1/2 tablespoon neutral oil to the pan. Add garlic and ginger, sauté gently until fragrant, about 30 seconds.
Combine: Return broccoli and steak to the pan. Pour in the sauce and toss everything together until the sauce thickens and coats evenly, about 1-2 minutes.
Serve hot with rice or noodles.