Prepare the Ingredients: Begin by prepping all ingredients. Slice the chicken breasts thinly, shred the cabbage, and thinly slice the onion, carrot, and bell pepper. Mince the garlic and ginger for a fresh burst of flavor.

Cook the Chicken: In a spacious skillet or wok, warm 1 tablespoon of oil over medium-high heat. Incorporate the thinly sliced chicken, seasoning it with salt and freshly cracked black pepper. Sauté for approximately 5-6 minutes, or until the chicken achieves a golden-brown color and is fully cooked. Once done, transfer the chicken to a plate and set aside.

Sauté the Aromatics: In the same skillet, pour in the additional tablespoon of oil. Add the sliced onion, garlic, and ginger, and sauté for 1-2 minutes until fragrant.

Add Vegetables: Incorporate the julienned carrots, sliced bell pepper, and shredded cabbage into the skillet. Stir-fry the vegetables for 3-5 minutes, or until they start to soften but still retain some crispness.

Combine the Ingredients: Return the cooked chicken to the skillet. Pour in the soy sauce, rice vinegar, and oyster sauce (if using), stirring well to coat all ingredients. Add crushed red pepper flakes if you like a bit of heat.

Final Touches: Stir everything together and cook for an additional 2-3 minutes to allow the flavors to meld. Top with a scattering of sesame seeds and finely chopped green onions for an appealing garnish.

Serve and Enjoy: Serve the stir-fry hot, on its own or with steamed rice or noodles for a heartier meal. Enjoy the fresh flavors and vibrant colors of this delicious stir-fry!