Prep the drumsticks: Pat the chicken dry with paper towels. This helps the skin crisp up and lets the seasoning stick.
Make the marinade: In a bowl, whisk together olive oil, apple cider vinegar, smoked paprika, garlic powder, onion powder, salt, pepper, and chili powder if using.
Marinate: Add drumsticks to a large bag or bowl, pour in the marinade, and toss to coat.
Let sit for at least 20–30 minutes, or up to 8 hours in the fridge.
Preheat: Heat the oven to 425°F (220°C). Line a rimmed baking sheet with foil and set a wire rack on top. Lightly oil the rack.
For grilling, preheat to medium-high and oil the grates.
Bake or grill the first cook: Arrange drumsticks on the rack or grill. Cook for 20 minutes, turning once halfway if grilling.
Mix the glaze: Stir together the BBQ sauce and ranch dressing in a small bowl until smooth.
Glaze and finish: Brush the drumsticks generously with the BBQ ranch mixture. Return to the oven or grill for 10–15 more minutes, glazing once more halfway.
The skin should be sticky and caramelized.
Check doneness: Use an instant-read thermometer. Aim for 175–185°F in the thickest part for tender, pull-away meat. The juices should run clear.
Rest and serve: Let the chicken rest 5 minutes. Brush with a final thin layer of sauce and sprinkle with chopped parsley or chives.