
Use a meat mallet or tenderizer to even out the thickness of the chicken thigh fillets for even cooking. If unavailable, use the back of a knife. Pat the chicken dry with kitchen paper, then lightly season with salt and pepper. Set aside.
In a small pot, combine the teriyaki sauce ingredients and bring to a boil over medium heat, stirring frequently until the sugar dissolves. Strain out the ginger and green onion, then set the sauce aside.
Heat a pan over medium-high heat until it starts to sizzle. Add the cooking oil and spread it evenly across the pan's surface. Place the chicken in the pan and cook for about 3 minutes, or until browned.Flip the chicken over, reduce the heat to medium-low, and cover with a lid. Continue cooking until the chicken is about 70% done (approximately 3 minutes). At this stage, the chicken should be firm and opaque on the outside but slightly pink in the center.
Open the lid and transfer the chicken to a plate. Carefully wipe away any excess liquid from the pan.
Return the chicken to the pan and pour the teriyaki sauce over it, reserving about 1/4 cup. Simmer the chicken over medium heat for about 3 minutes, then flip it and simmer for an additional 2 minutes, or until fully cooked. While simmering, frequently spoon the sauce over the chicken to give it a glossy finish.
Once the chicken is fully cooked, remove it from the pan and set it aside. If the sauce hasn’t thickened yet, increase the heat to medium-high and simmer to reduce the sauce, which should take 2 to 4 minutes. Alternatively, you can add a starch slurry for quicker thickening. Once the sauce reaches your desired consistency, return the chicken to the pan briefly to coat it in the sauce before serving.
Transfer the chicken to a cutting board and slice it into bite-sized pieces.
Serve the chicken over a bowl of rice with your choice of vegetables. If desired, drizzle the reserved teriyaki sauce over the bowl, then garnish with green onion and sesame seeds. Enjoy!