Prep the oven and pan: Heat the oven to 425°F (220°C). Set a wire rack over a rimmed baking sheet and lightly coat the rack with cooking spray.
The rack helps the skin crisp all over.
Pat the chicken dry: Use paper towels to dry the thighs thoroughly. Dry skin equals crispy skin.
Mix the seasoning paste: In a bowl, combine olive oil, garlic, Parmesan, salt, pepper, Italian seasoning, smoked paprika, and the lemon zest. Stir into a thick paste.
Season the thighs: Gently lift the skin of each thigh and rub a small amount of paste directly on the meat. Spread the rest over the skin and sides, coating evenly.
Arrange on the rack: Place thighs skin-side up on the prepared rack.
Leave space between pieces so heat can circulate.
Roast: Bake for 30–35 minutes, until the skin is well browned and the internal temperature reaches 175–185°F. Thighs taste best above 175°F because the collagen melts and the meat turns silky.
Make a quick pan sauce (optional but great): Remove the pan and set the thighs on a plate to rest. Pour the chicken broth onto the hot sheet pan and scrape up the browned bits.
Squeeze in 1–2 teaspoons lemon juice. Taste and adjust salt. Spoon over the thighs.
Finish and serve: Sprinkle with fresh parsley and a little extra Parmesan if you like.
Serve with a simple green salad, steamed broccoli, or roasted asparagus.