Preheat your oven to 200°C (390°F). Pat the chicken thighs dry with paper towels to remove excess moisture, helping the skin crisp up nicely.
In a small bowl, crush the garlic cloves to release their aroma. Grate the Parmesan cheese and set aside.
Season the chicken generously with salt, pepper, and red pepper flakes if using. Rub the seasonings into the skin for even flavor.
Heat the olive oil in your oven-safe skillet over medium-high heat until shimmering and hot. Carefully place the chicken thighs skin-side down and sear without moving for about 5-7 minutes, until the skin turns a deep golden brown and becomes crispy.
Flip the chicken thighs using tongs and cook for another 3 minutes, just to brown the other side slightly. During the last minute of searing, sprinkle the grated Parmesan evenly over the chicken, allowing it to melt and become fragrant.
Transfer the skillet to the preheated oven and roast for 12-15 minutes, or until the internal temperature reaches 75°C (165°F). The skin should remain crispy, and the meat tender and juicy.
Remove the skillet from the oven and let the chicken rest for 5 minutes. Squeeze fresh lemon over the top for brightness and sprinkle with chopped parsley for color.
Serve the chicken hot, with crispy skin, melting Parmesan, and fragrant garlic. Enjoy the aromatic, savory flavors with your favorite sides.