1. Marinate the Chicken: In a mixing bowl, toss chicken pieces with cornstarch, salt, and pepper until evenly coated. Allow it to sit and marinate for about 10 minutes.

2. Make the Sauce: In a small bowl, whisk together chicken broth, soy sauce, oyster sauce, honey, cornstarch, minced garlic, and grated ginger until well combined. Set this flavorful sauce aside for later use.

3. Cook the Chicken: Heat 1 tablespoon of oil in a large skillet or wok over medium-high heat. Add the marinated chicken in a single layer and cook for about 1 minute undisturbed to achieve a nice sear. Stir fry for an additional 4 to 5 minutes until the chicken is golden and cooked through. Remove chicken from the skillet and place it in a separate bowl.

4. Stir Fry the Vegetables: In the same skillet, add the remaining tablespoon of oil. Toss in the sliced onion, broccoli florets, and sliced mushrooms. Stir fry for approximately 3 to 4 minutes, ensuring the broccoli remains bright green and the mushrooms become tender.

5. Add the Sauce: Reduce the heat to medium-low and give the sauce a quick stir before pouring it over the vegetables. Let it simmer for 2 to 3 minutes, stirring occasionally until the sauce thickens and becomes glossy.

6. Combine and Serve: Return the cooked chicken to the skillet, tossing everything together to ensure an even coating with the sauce. Allow it to heat for 1 more minute. Serve immediately over fluffy steamed rice or noodles, topping with sesame seeds and sliced green onions for that perfect finish.