01 - Pat the chicken thighs dry with paper towels and season generously on all sides with salt and freshly ground black pepper.
02 - Heat the olive oil and butter together in a large skillet with a lid over medium-high heat until the butter is melted and foaming.
03 - Place the chicken thighs skin side down in the skillet and sear for 5 to 6 minutes until the skin is deeply golden brown and crispy. Flip and sear the other side for an additional 5 to 6 minutes. Remove the chicken from the skillet and set aside on a plate.
04 - Reduce the heat to medium. Add the diced onion to the same skillet and cook for 2 to 3 minutes, stirring occasionally, until softened and translucent. Add the minced garlic and cook for 1 minute until fragrant, being careful not to let it brown.
05 - Pour in the chicken broth, using a wooden spoon to scrape up all the caramelized brown bits from the bottom of the skillet. Let the broth simmer for 1 to 2 minutes to reduce slightly.
06 - Reduce the heat to medium-low. Stir in the heavy cream, dried thyme, dried rosemary, dried oregano, and chopped parsley. Whisk gently until the sauce is smooth and well combined.
07 - Return the seared chicken thighs to the skillet, placing them skin side up. Spoon some of the sauce over each thigh. Cover with the lid and let simmer gently for 15 minutes, or until the chicken is cooked through to an internal temperature of 165°F and the sauce has thickened to a silky consistency.
08 - Remove the lid and taste the sauce, adjusting the seasoning with additional salt and pepper if needed. Garnish generously with extra fresh parsley and serve immediately over mashed potatoes, rice, or alongside crusty bread.