In a bowl, whisk together soy sauce, honey, brown sugar, rice vinegar, sesame oil, garlic, and ginger.
Place the chicken thighs in a zip-top bag or shallow dish and pour in half of the marinade.
Cover and marinate in the fridge for at least 10 minutes (or up to 24 hours for extra flavor!).
Set aside the remaining half of the marinade—this will become your teriyaki sauce.
Heat 1 tablespoon of vegetable oil in a large pan over medium-high heat.
Remove the chicken from the marinade and pat it dry with paper towels (this helps it sear better).
Cook for 4-5 minutes per side until golden brown and cooked through (internal temp: 165°F).
Remove the chicken from the pan and let it rest while you make the glaze.
Pour the remaining marinade into the pan and bring to a simmer over medium heat.
In a small bowl, mix 1 tablespoon cornstarch with 2 tablespoons water to create a slurry.
Stir the slurry into the sauce and cook for 1-2 minutes until thick and glossy.
Slice the cooked chicken into strips and return it to the pan.
Toss to coat evenly in the thick teriyaki sauce.
Sprinkle with sesame seeds and sliced green onions for the perfect finishing touch.
Serve hot over steamed rice or veggies for a complete meal!