Preheat and prep: Heat the oven to 425°F (220°C).
Pat the chicken thighs very dry with paper towels. Dry skin equals crisp skin.
Make the Cajun rub: In a small bowl, mix smoked paprika, sweet paprika, garlic powder, onion powder, oregano, thyme, salt, cayenne, black pepper, and brown sugar if using.
Season the chicken: Rub the thighs all over with olive oil. Sprinkle the spice mix evenly on both sides, focusing extra on the skin side.
Press it in so it sticks.
Sear for crisp skin: Heat a large oven-safe skillet over medium-high heat. Add a thin layer of oil. Place thighs skin-side down and sear for 4–5 minutes, until the skin is deeply browned and crisp.
Don’t move them too much.
Finish in the oven: Flip the thighs skin-side up and transfer the skillet to the oven. Roast for 15–20 minutes, until the thickest part reaches 175–185°F for tender, juicy thighs.
Rest and finish: Let the chicken rest 5 minutes. Squeeze a little lemon over the top and sprinkle with parsley or green onions.
Serve: Plate with rice, corn, slaw, sautéed greens, or roasted sweet potatoes.
Spoon any pan juices over the top.