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 heat until shimmering.
Place the chicken thighs skin-side down in the skillet. Place a smaller heavy skillet or a heatproof weight on top of the chicken to press it down.
Cook for 12 minutes without moving the chicken to achieve crispy skin.
Remove the smaller skillet or weight and flip the chicken thighs over.
Cook for an additional 8 minutes, or until the chicken is cooked through and reaches an internal temperature of 165°F (74°C). Remove the chicken from the skillet and set aside on a plate.
Reduce heat to medium-low. Add the minced garlic to the skillet and sauté for 30 seconds until fragrant.
Pour in the chicken broth and lemon juice, scraping up any browned bits from the bottom of the skillet with a wooden spoon.
Simmer the sauce for 3-4 minutes until slightly reduced.
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.