In a small bowl, whisk together honey, soy sauce, minced garlic, grated ginger, sesame oil, and red pepper flakes (if using). Set aside.
In a separate small bowl, whisk together cornstarch and water until smooth. Set aside.
Pat chicken thighs dry with paper towels. Season with salt and pepper.
Heat a large skillet over medium-high heat. Add chicken thighs in a single layer and cook for 5-7 minutes per side, or until browned and cooked through.
Remove chicken from the skillet and set aside. Pour off any excess fat from the skillet.
Pour the honey garlic sauce into the skillet and bring to a simmer.
Whisk the cornstarch slurry again and gradually add it to the simmering sauce, stirring constantly until the sauce thickens.
Return the chicken thighs to the skillet and toss to coat them in the sauce.
Cook for another 1-2 minutes until the chicken is heated through and coated with the glossy sauce.
Serve hot, garnished with chopped parsley and toasted sesame seeds.
Notes
Serve with steamed rice and your favorite vegetables for a complete meal.