Set a wire rack inside a rimmed baking sheet, and set aside.

In a small bowl, combine brown sugar, chili powder, garlic powder, onion powder, paprika, salt and pepper, and cayenne. Set aside

Take each chicken thigh, and use a sharp paring knife to make 2-3 short slashes into the skin of the chicken. Be careful not to cut the meat.

Now use your hands to coat each pieces of chicken with the spice mixture, gently lift the skin, and place spice mixture underneath it, while leaving it still attached to the chicken. Also spread it on top of the chicken skin.

Place each thigh, skin side up, on the prepared baking sheet rack.

Tent with aluminum foil, and put baking sheet into the refrigerate for at least 6 hours, up to 24 hours, usually let it sit overnight, or prep in the morning for dinner.

After chicken has had a chance to sit for at least 6 hours, preheat the oven to 425 degrees F with the rack in the middle position.

Remove foil, and roast chicken until the internal temp on the smallest piece is 140 degrees (about 15 minutes).

Then increase your oven temperature to 500 degrees F and continue roasting until chicken is brown, crispy, and internal temp is 170 degrees, about 10-15 minutes.

Remove chicken pieces as they reach the correct temperature, and set on a wire rack to let cool.

Refrigerate or serve!