Follow these simple steps to create your own Panda Express Beijing Beef at home:

1. Prepare the Beef: Thinly slice the flank steak against the grain to ensure tenderness.
2. Coat the Beef: In a bowl, toss the sliced beef with cornstarch until evenly coated. This will help create a crispy texture when cooked.
3. Heat Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.
4. Cook the Beef: Add the coated beef to the skillet in a single layer. Cook for 2-3 minutes until browned, then flip and cook for another 2-3 minutes. Remove the beef from the skillet and set aside.
5. Sauté Vegetables: In the same skillet, add the sliced onions and bell peppers. Stir-fry for 3-4 minutes until they begin to soften.
6. Make the Sauce: In a separate bowl, whisk together soy sauce, hoisin sauce, sugar, rice vinegar, minced garlic, and minced ginger.
7. Combine: Return the cooked beef to the skillet with the vegetables. Pour the sauce over the mixture and stir to coat everything evenly. Cook for another 2-3 minutes until heated through.
8. Season: Taste and adjust seasoning with salt and pepper as needed.
9. Garnish: Remove from heat and garnish with sliced green onions, if desired.

These steps will guide you in creating this incredible dish effortlessly.