In a mixing bowl, combine chicken thighs with soy sauce, dark soy sauce, oyster sauce, black pepper powder, and cornstarch. Allow to marinate for at least 10 minutes.

Heat a non-stick skillet over medium heat and add the oil. Once shimmering, add the marinated chicken thighs to the pan.

Pan-fry the chicken for about 5-7 minutes, turning occasionally until golden brown and fully cooked.

Sprinkle the white parts of the scallions into the pan and stir, cooking for an additional 2-3 minutes.

Add the green parts of the scallions to the pan and cook for just 10-20 seconds before serving.

Remove from heat and serve hot over rice or noodles, garnished with additional scallions.