Prep your oven and pan: Preheat the oven to 425°F (220°C). Use a large oven-safe skillet (cast iron works best). Pat the chicken thighs dry with paper towels to help the skin crisp.
Mix the seasoning: In a small bowl, combine 1.5 tablespoons lemon pepper seasoning, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1/2 teaspoon smoked paprika, and 1 teaspoon kosher salt.
Add a few grinds of black pepper if your lemon pepper blend is mild.
Season the chicken: Zest one lemon over the chicken, then sprinkle the seasoning blend evenly on both sides, focusing extra on the skin. Press gently to help it stick.
Sear skin-side down: Heat 1 tablespoon olive oil in the skillet over medium-high. When shimmering, add the chicken skin-side down.
Cook without moving for 6–8 minutes, until the skin is deeply golden and releases easily.
Add butter and flip: Reduce heat to medium, add 1–2 tablespoons butter around the chicken, and flip the thighs. Baste briefly with the melted butter for extra flavor.
Finish in the oven: Transfer the skillet to the oven and roast for 12–18 minutes, until the thickest part of the thighs reaches 165°F (74°C). Size varies, so check with a thermometer starting at 12 minutes.
Brighten with lemon: Remove from the oven.
Squeeze the juice of half a lemon over the chicken. Let rest 5 minutes so the juices settle.
Garnish and serve: Spoon pan juices over the chicken. Sprinkle with chopped fresh parsley and extra lemon zest if you like.
Serve with roasted asparagus, sautéed green beans, or a simple arugula salad.