Preheat your oven to 400°F (200°C). Line a large baking dish or rimmed sheet pan with aluminum foil and lightly grease with olive oil or cooking spray.
Remove the chicken pieces from packaging and pat completely dry on all sides with paper towels. Dry skin is essential for browning and helps the seasoning adhere properly.
In a small bowl, mix together the garlic powder, onion powder, smoked paprika, salt, black pepper, and cayenne pepper (if using) until evenly combined.
Drizzle olive oil over the chicken pieces and rub to coat evenly, then sprinkle the dry rub over all surfaces, massaging it into the skin and under any loose skin flaps.
Place the seasoned chicken pieces skin-side up in the prepared baking dish, leaving at least 1 inch of space between each piece to avoid steaming.
Bake uncovered on the middle rack for 25 minutes. This initial bake partially cooks the chicken and renders the fat from the skin before adding sauce.
Remove the pan from the oven and use a basting brush to apply a generous, even layer of BBQ sauce over the top and sides of each chicken piece. Return to the oven for 10 minutes.
Remove the pan, apply a second thicker coat of BBQ sauce, then return to the oven for another 10–15 minutes until the internal temperature reaches 165°F (74°C) and the sauce is caramelized and sticky.
For extra caramelization, switch to broil on high for the last 2–3 minutes, watching carefully to prevent the sauce from burning.
Let the chicken rest for 5 minutes before serving to allow the juices to redistribute. Garnish with chopped fresh parsley if desired and serve with extra BBQ sauce on the side.