Pat the chicken very dry. Use paper towels to blot the skin thoroughly. The drier the skin, the crispier it gets.
If you have time, place the thighs uncovered in the fridge for 30–60 minutes to dry the skin even more.
Preheat the oven to 425°F (220°C). Place a wire rack on a rimmed baking sheet for best results. If you don’t have a rack, line the pan with foil and lightly oil it.
Season generously. In a small bowl, mix salt, pepper, garlic powder, onion powder, smoked paprika, and thyme. Drizzle the thighs with olive oil, then sprinkle the spice blend evenly on both sides.
Press gently so it adheres.
Arrange skin-side up. Place the thighs on the rack or pan, leaving space between them so hot air can circulate.
Bake until crisp and cooked through. Roast for 35–45 minutes, depending on size. The skin should be deep golden and crackly. The internal temperature should read 175–190°F in the thickest part near the bone for the most tender, juicy thighs.
Optional: Broil for extra crunch. If you want even more crispy skin, broil on high for 1–3 minutes at the end.
Watch closely to avoid burning.
Rest and serve. Let the chicken rest for 5 minutes so the juices settle. Finish with a squeeze of lemon and a sprinkle of parsley if you like.