Preheat the oven to 200C/400F.
Season the chicken thighs with salt and pepper.
Heat a cast iron skillet over medium-high heat. Add olive oil and butter. Cook chicken thighs, skin side down, for 6-8 minutes, or until golden and crispy
Flip the chicken thighs, add minced garlic, and transfer the skillet to the oven.
Bake for 12-15 minutes until the chicken reaches an internal temperature of 165°F (74°C).
Let chicken thighs rest in the skillet for a few minutes.