Preparation:

Step1: Prepare the Beef

1. Thinly slice the beef against the grain for tender pieces.
2. Toss the beef slices in soy sauce and cornstarch, ensuring they are evenly coated. Let them marinate for 15-20 minutes while preparing the other ingredients.

Step2: Mix the Sauce

1. In a small bowl, combine soy sauce, hoisin sauce, rice vinegar, chili garlic sauce, sesame oil, sugar, and ground Szechuan peppercorns. Whisk until smooth and set aside.

Step3: Stir-Fry the Beef

1. Heat a wok or large skillet over high heat. Add 1 tablespoon of vegetable oil.
2. Once the oil is hot, stir-fry the beef in small batches for 2-3 minutes until browned. Remove and set aside.

Step4: Cook the Vegetables

1. In the same wok, add the remaining 1 tablespoon of oil.
2. Stir-fry garlic, ginger, and dried red chilies (if using) until fragrant, about 30 seconds.
3. Add the bell pepper, broccoli florets, and green onions. Cook for 2-3 minutes until the vegetables are slightly tender but still crisp.

Step5: Combine and Serve

1. Return the cooked beef to the wok.
2. Pour in the prepared sauce and toss everything to coat evenly. Stir-fry for another 1-2 minutes until the sauce thickens and coats the beef and vegetables.
3. Remove from heat and serve hot.