Preheat your grill or oven to 400°F (200°C). If using the oven, line a baking sheet with foil for easy cleanup.
In a small bowl, mix together the smoked paprika, garlic powder, onion powder, cayenne pepper (if using), salt, and pepper. This will be your dry rub.
Pat the chicken thighs dry with a paper towel. Rub each thigh with olive oil, ensuring they are well coated.
Sprinkle the dry rub evenly over the chicken thighs, making sure to evenly cover both sides.
If grilling: Place the chicken thighs skin-side down on the grill. Cook for about 10-12 minutes, then flip and brush with the sugar-free BBQ sauce. Continue grilling for another 10-12 minutes, basting with more BBQ sauce halfway through or until the internal temperature reaches 165°F (75°C).
If baking: Place marinated chicken thighs on the prepared baking sheet, skin-side up. Bake for 25-30 minutes, then brush with sugar-free BBQ sauce and return to the oven for an additional 10 minutes, or until the chicken reaches an internal temperature of 165°F (75°C).
Remove from grill/oven and let rest for 5 minutes. Garnish with freshly chopped parsley.
Notes
Serve on a rustic wooden board with fresh parsley and a side of grilled vegetables.