Slice 1 pound of boneless skinless chicken breast thinly against the grain. Toss the chicken with 1 tablespoon soy sauce and let it marinate for 5-10 minutes.

While the chicken marinates, prepare the sauce by whisking together 2 tablespoons soy sauce, 1 tablespoon halal oyster sauce (if using), 2 teaspoons sesame oil, 1 tablespoon rice vinegar, and a cornstarch slurry (1 teaspoon cornstarch mixed with 2 tablespoons water).

Heat 1 tablespoon vegetable oil in a large wok or skillet over medium-high heat until almost smoking. Add the marinated chicken in a single layer and cook undisturbed for about 1 minute, then stir and cook for an additional 1-2 minutes until nearly done. Transfer the chicken to a plate.

In the same pan, add the remaining tablespoon of vegetable oil. Sauté 3 minced garlic cloves and 1 tablespoon grated ginger for about 30 seconds until fragrant. Then add 3 cups shredded cabbage, 1 julienned carrot, and 1 sliced red bell pepper, stir-frying for 2-3 minutes until the vegetables are crisp-tender.

Return the chicken to the pan along with 3 chopped green onions and, if desired, ½ teaspoon crushed red pepper flakes. Pour in the prepared sauce and stir constantly for 30-60 seconds until the sauce thickens and evenly coats the chicken and vegetables.

Serve the stir-fry immediately over steamed jasmine rice or noodles. Garnish with toasted sesame seeds for an extra nutty flavor and visual appeal.