Creating Mongolian Chicken is simple if you follow these steps:

1. Prep the Ingredients: Slice the chicken and vegetables, and mince the garlic and ginger.
2. Marinate the Chicken: In a bowl, mix the chicken with soy sauce, salt, and pepper. Let it marinate for about 10 minutes.
3. Heat the Oil: In a large skillet or wok, heat the vegetable oil over medium-high heat.
4. Cook the Chicken: Add the marinated chicken to the skillet and cook until golden brown, about 5-7 minutes. Remove the chicken from the skillet and set aside.
5. Sauté the Vegetables: In the same skillet, add the broccoli, bell pepper, and carrots. Stir-fry for about 3-4 minutes until they are tender-crisp.
6. Add Garlic and Ginger: Stir in the minced garlic and grated ginger, cooking for an additional 1 minute until fragrant.
7. Prepare the Sauce: In a small bowl, whisk together brown sugar, cornstarch, and water until smooth. Pour this mixture into the skillet.
8. Combine Chicken and Sauce: Return the chicken to the skillet and stir everything together, cooking for another 2-3 minutes until the sauce thickens.
9. Adjust Seasoning: Taste and adjust seasoning with additional salt or pepper if needed.
10. Garnish and Serve: Remove from heat and garnish with chopped green onions and sesame seeds.

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