Preheat the oven to 425. Optional - spray oven proof skillet with cooking spray.
Trim off excess fat and skin from the thighs. Pat dry and season on both sides with salt and pepper. Place in the skillet.
In a small bowl, whisk together the red pepper flakes, brown sugar, fish sauce, soy sauce and grated ginger. Pour over the chicken and turn the chicken to coat.
Place the skillet in the oven and roast skin side down for 30 minutes. Turn the chicken over and roast for 15 more minutes.
Optional - for more color and caramelization you can broil the chicken for 2-5 minutes, but do not walk away!
Serve garnished with cilantro.
Video
Notes
If using boneless, skinless thighs - you probably won't need the last 15 minutes. Simply roast 15 minutes, turn and continue roasting for 15 more minutes.