Pat the chicken thighs dry with paper towels. Season both sides with kosher salt and black pepper.
Heat olive oil in a large skillet over medium-high heat until shimmering.
Place the chicken thighs skin-side down in the skillet. Cook without moving for 7-8 minutes until the skin is golden brown and crispy.
Flip the chicken thighs and cook for another 7 minutes until the internal temperature reaches 165°F (74°C). Remove the chicken from the skillet and set aside on a plate.
Reduce heat to medium. Add minced garlic to the skillet and sauté for 30 seconds until fragrant, stirring constantly to prevent burning.
Add Dijon mustard, chicken broth, lemon juice, and dried thyme to the skillet. Stir well to combine and bring the sauce to a simmer.
Cook the sauce for 2-3 minutes until slightly thickened.
Stir in the unsalted butter until melted and the sauce is glossy.
Return the chicken thighs to the skillet, spooning some sauce over the top. Cook for 1-2 minutes to reheat the chicken and meld flavors.
Sprinkle chopped fresh parsley over the chicken before serving.