In a medium bowl, combine the sliced beef with cornstarch, soy sauce, and sesame oil. Toss well and let marinate for 15 minutes.

In a small bowl, whisk together the soy sauce, oyster sauce, hoisin sauce, honey, brown sugar, sesame oil, rice vinegar, and red pepper flakes. Set aside.

Heat 1 tablespoon vegetable oil in a large wok or skillet over high heat.

Add the beef in a single layer and cook for 2 to 3 minutes until browned. Remove from the pan and set aside.

Add the remaining tablespoon of vegetable oil to the pan.

Add the broccoli, carrots, mushrooms, and bell pepper. Stir-fry for 4 to 5 minutes until slightly tender but still crisp.

Stir in the garlic and ginger and cook for 30 seconds until fragrant.

Add the cold cooked rice and break up any clumps with a spatula.

Stir-fry the rice for 3 to 4 minutes until heated through.

Pour the prepared sticky sauce evenly over the rice and stir until everything is well coated.

Return the cooked beef to the pan and toss everything together for 2 minutes until heated through.

Stir in the sliced green onions.

Remove from the heat and let the fried rice rest for 5 minutes if desired.

Garnish with sesame seeds and additional green onions before serving.