Creating Mongolian Chicken is straightforward if you follow these simple steps:

1. Prep the Chicken: Slice the chicken breasts into thin strips and set aside.
2. Make the Sauce: In a bowl, mix soy sauce, brown sugar, cornstarch, and water. Stir until well combined and set aside.
3. Heat the Oil: In a large skillet or wok, heat vegetable oil over medium-high heat.
4. Cook the Chicken: Add the sliced chicken to the skillet. Stir-fry for about 5-7 minutes or until cooked through and golden brown. Remove the chicken from the skillet and set aside.
5. Sauté the Vegetables: In the same skillet, add broccoli, bell pepper, and carrot. Stir-fry for 3-4 minutes until the vegetables are tender-crisp. Add garlic and ginger, and stir for an additional minute.
6. Combine the Chicken and Sauce: Return the cooked chicken to the skillet. Pour the sauce over the chicken and vegetables, stirring to coat everything evenly.
7. Thicken the Sauce: Cook for another 2-3 minutes until the sauce thickens, stirring continuously.
8. Add Heat (Optional): If you like some spice, sprinkle in crushed red pepper flakes and mix well.
9. Garnish: Remove from heat and garnish with chopped green onions and sesame seeds.
10. Serve: Transfer to a serving dish and enjoy your Mongolian Chicken!

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