Pat the chicken thighs dry with paper towels, then season generously with salt and pepper on both sides.

In a large oven-safe skillet, heat 1 tablespoon of olive oil and 1 tablespoon of butter over medium-high heat. Place the chicken thighs in the skillet, skin-side down. Sear for about 7-10 minutes, or until the skin is golden brown and crispy. Flip the chicken and sear the other side for 2-3 minutes. Remove the chicken from the skillet and set aside.

In the same skillet, reduce the heat to medium and add the remaining 1 tablespoon of butter. Add the minced garlic and sauté for about 1 minute until fragrant.

Stir in the lemon zest, lemon juice, dried oregano, paprika, and crushed red pepper flakes (if using). Pour in the chicken broth, stirring to combine and scraping up any browned bits from the bottom of the skillet.

Return the seared chicken thighs to the skillet, skin-side up, making sure they are in a single layer. Transfer the skillet to the oven and bake at 375°F (190°C) for 25-30 minutes, or until the chicken is cooked through (internal temperature should reach 165°F/74°C) and the skin is crispy.

Remove the skillet from the oven. Garnish the chicken thighs with chopped fresh parsley and lemon slices. Serve hot with the pan sauce spooned over the top.