Begin by prepping your ingredients for the stirfry. Thinly slice the yellow onion and bell pepper, julienne the carrot, mince the garlic, chop the cabbage, and dice the chicken.

In a large skillet, heat a tablespoon of unsalted butter over medium-high heat. Add the diced chicken and sauté for about 5-7 minutes until cooked through.

In the same pan, add more butter if needed, and toss in the sliced onion and minced garlic. Stir-fry until fragrant.

Add the chopped cabbage, bell pepper, and julienned carrot. Cook for about 5 minutes until the vegetables are crisp-tender.

Return the cooked chicken to the pan. Pour in the soy sauce, oyster sauce, sesame oil, black pepper, and red pepper flakes. Stir well and cook for another 2-3 minutes.

For a thicker sauce, mix cornstarch with water and add to the pan, stirring constantly until thickened.

Remove from heat and serve hot over rice or noodles.