Savory Mongolian Beef

Marinating the Beef:

1. In a bowl, combine the thinly sliced flank steak with the marinade ingredients: soy sauce, rice wine or sherry, cornstarch, sesame oil, and brown sugar.
2. Mix well, ensuring each piece of beef is coated. Let it marinate for about 20-30 minutes.
3. Preparing the Sauce:
4. In another bowl, whisk together the soy sauce, water, brown sugar, cornstarch, and sesame oil until the sugar and cornstarch dissolve. Set the sauce aside.

Stir-Frying:

1. Heat a tablespoon of vegetable oil in a wok or large skillet over high heat.
2. Add the marinated beef slices, spreading them out to ensure even cooking. Allow them to sear for about 1-2 minutes on each side until they turn brown and slightly crispy. Remove the beef from the pan and set it aside.

Creating the Flavor Base:

1. In the same pan, add another tablespoon of oil if needed. Sauté the minced garlic, ginger, and red pepper flakes for about 30 seconds until aromatic.
2. Toss in the sliced red bell pepper and onion. Stir-fry for 2-3 minutes until they begin to soften.

Combining Flavors:

1. Return the seared beef to the pan, combining it with the sautéed vegetables.
2. Give the prepared sauce a quick stir and pour it over the beef and vegetables.

Final Touches:

1. Toss everything together, allowing the sauce to coat the beef and vegetables evenly. Cook for an additional 1-2 minutes until the sauce thickens.

Serving:

1. Once the Mongolian Beef is cooked to perfection, remove it from heat.
2. Serve the dish over steamed rice and garnish with sliced green onions and toasted sesame seeds for an added burst of flavor and texture.