1. Heat oven to 400 degrees. In a small bowl, combine the chile powder, cumin, paprika, plus salt and pepper to taste. Rub the chicken all over with the chile mix.

2. Add the olive oil to a large cast-iron or other ovenproof skillet, and swirl to cover bottom. Add the onion rounds in a single layer, then the thyme. Add chicken, skin side up. Transfer to oven, and bake until the chicken has cooked through, 30 to 40 minutes.

3. Let chicken cool slightly. Using your fingers, remove the bones. Slice each breast, crosswise, into four or five pieces. Serve with the roasted onion rounds and thyme.