Preheat the oven to 400°F. Line a half-sheet pan with a triple layer of paper towels, then place the chicken pieces in a single layer. Then, cover the top of the chicken with another triple layer of paper towels. Gently press down on the chicken pieces to dry them as much as possible.
In a small bowl combine baking powder, garlic powder, onion powder, chili powder, smoked paprika, dried thyme, dried oregano, mustard powder, white pepper, black pepper, and Kosher salt. Set aside until ready to use.
Once the chicken is dry, place the pieces in a large bowl. Then, pour the olive oil over the chicken. Put on a pair of vinyl gloves and use your hands to toss the chicken until all the pieces are well coated in the oil.
Sprinkle the mixed spices over the chicken and use your gloved hands to toss the chicken again, so that all of the pieces are well coated in the spice mixture.
Line a half-sheet pan with extra-wide, heavy-duty aluminum foil. Place a half-sheet wire rack inside the pan and generously spray the rack with non-stick cooking spray. Then, use a pair of tongs to transfer the prepared chicken pieces to the wire rack. Allow the chicken to rest for 30 minutes before baking; this helps the flavors of the dry rub to season the meat all the way to the bone.
Bake in a 400°F oven for 25 minutes. Remove the pan from the oven and increase the oven temperature to 425°F. Brush both sides of the chicken pieces with about half of the barbecue sauce, using tongs to turn the pieces. Make sure the skin side is facing down when you are finished. (It's ok if you have a little bit of sauce left, you can use it before broiling the chicken.) Once the oven temperature reaches 425°F, return the pan and bake for 10 minutes.
After 10 minutes, remove the pan from the oven, and again, brush both sides with the remaining sauce, making sure the skin side is facing up when you are finished. Return the pan to the oven and bake for 10 more minutes, or until the internal temperature reaches 165°F.
Remove the pan from the oven and set the broiler to high. Turn the chicken pieces skin side down and brush with any remaining sauce. Broil the chicken for 3-5 minutes, make sure to keep an eye on it. The sauce can go from caramelized to burnt in a matter of seconds.
Remove the pan from the oven and flip the pieces over with a pair of tongs, making sure the skin side is facing up this time. Brush any remaining sauce over the pieces. Return the pan to the oven and broil for 3-5 minutes, again make sure to keep an eye on it. (The first round of broiling will likely take longer than the second.) Allow the chicken to rest for 5-10 minutes before serving.
Yield 6 servings