In a small Mixing Bowl, whisk together the 3 tbsp olive oil, 1 lemon zested and juiced zest, 1 lemon zested and juiced juice, minced 4 cloves garlic minced, 1 tsp fresh thyme leaves or ½ tsp dried thyme, 1 tbsp fresh rosemary finely chopped, or ½ tsp dried rosemary, 2 tbsp fresh parsley finely chopped, 1 tsp kosher salt, ½ tsp black pepper freshly ground, and ½ tsp onion powder until combined.

Pat the 4 bone-in, skin-on chicken thighs about 2 ½ lb total, patted dry completely dry with paper towels — this is the key to crispy skin. Place them in a shallow dish or Ziploc Bag and pour about two-thirds of the marinade over the 4 bone-in, skin-on chicken thighs about 2 ½ lb total, patted dry. Reserve the remaining marinade for basting. Toss to coat well. Marinate at room temperature for 20–30 minutes, or refrigerate for up to 8 hours for deeper flavor.

Preheat your Oven to 400°F. Heat 1 tbsp of 3 tbsp olive oil in a large oven-safe Cast Iron Skillet over medium-high heat until shimmering.

Remove the 4 bone-in, skin-on chicken thighs about 2 ½ lb total, patted dry from the marinade and shake off any excess. Place the thighs skin-side DOWN in the hot Cast Iron Skillet. Sear undisturbed for 5–6 minutes until the skin is deep golden brown and releases easily from the pan. Do not move them — patience here gives you the crispiest skin.

Flip the 4 bone-in, skin-on chicken thighs about 2 ½ lb total, patted dry skin-side UP. Brush the tops with the reserved marinade. Transfer the entire Cast Iron Skillet to the preheated Oven.

Use boneless, skinless breasts of even thickness. If over 1 inch thick, butterfly or pound to uniform thickness for faster, even cooking. Pat completely dry with paper towels — moisture kills a good sear. Season both sides generously with salt and pepper or your spice blend. Coat lightly with a high-heat oil (avocado or vegetable). Keep an Instant-Read Thermometer handy; target is 165°F.

Heat a heavy Skillet (cast iron or stainless) over medium-high. Add 1–2 tbsp high-heat oil and wait until it shimmers. Lay breasts away from you into the pan. Do not move them. Cook undisturbed 5–8 min on the first side until a deep golden-brown crust forms — if it resists lifting, it's not ready. Flip once and cook another 5–8 min. Drop heat to medium if the outside is browning too fast. Optional: add 1 tbsp butter in the last 2–3 min and baste. Total time: 10–16 min depending on thickness. Pull at 165°F internal temp.

Remove the Cast Iron Skillet from heat and swirl in the 1 tbsp unsalted butter until melted and the sauce looks glossy. Taste and adjust seasoning with 1 tsp kosher salt and ½ tsp black pepper freshly ground if needed. Spoon the pan sauce over the 4 bone-in, skin-on chicken thighs about 2 ½ lb total, patted dry, garnish with fresh 2 tbsp fresh parsley finely chopped and 1 lemon zested and juiced rounds, and serve immediately.