Pat the chicken thighs dry with paper towels. Season both sides with kosher salt and black pepper.
Heat the olive oil in a large oven-safe skillet over medium-high heat until shimmering.
Place the chicken thighs skin-side down in the skillet. Immediately place a heavy skillet or a cast iron pan on top of the chicken to press it down.
Cook for 10 minutes without moving the chicken, allowing the skin to become crispy and golden brown.
Remove the top skillet carefully. Flip the chicken thighs and cook for an additional 8 minutes, or until the internal temperature reaches 165°F (74°C). Remove the chicken from the skillet and set aside on a plate.
Reduce the heat to medium. Add the minced garlic to the skillet and sauté for 30 seconds until fragrant.
Pour in the chicken broth and lemon juice, scraping the bottom of the skillet with a wooden spoon to loosen any browned bits.
Simmer the sauce for 3-4 minutes until it reduces slightly.
Remove the skillet from heat and whisk in the unsalted butter until the sauce is smooth and glossy.
Return the chicken to the skillet and spoon the lemon pan sauce over the top.
Sprinkle with chopped fresh parsley before serving.