01 - Pat the chicken breasts dry with paper towels and season both sides evenly with kosher salt and freshly ground black pepper.
02 - Heat olive oil in a large skillet over medium-high heat. Once the oil shimmers, add the chicken breasts and sear until golden brown on both sides, about 4 to 5 minutes per side. Transfer the chicken to a plate and set aside.
03 - Reduce the heat to medium. Add the minced garlic and diced shallot to the skillet. Sauté for 1 to 2 minutes, stirring frequently, until fragrant and softened.
04 - Add the fresh thyme, parsley, and rosemary to the skillet. Stir to combine and cook for about 1 minute until the herbs release their aroma.
05 - Pour in the fresh lemon juice, lemon zest, and chicken broth. Use a wooden spoon to scrape up any browned bits from the bottom of the pan, incorporating them into the sauce.
06 - Return the seared chicken breasts to the skillet and spoon some of the sauce over the top. Cover with a lid and let simmer gently for 8 to 10 minutes, or until the chicken reaches an internal temperature of 165°F.
07 - Uncover the skillet and add the unsalted butter. Swirl the pan gently until the butter melts completely and the sauce becomes glossy and slightly thickened.
08 - Transfer the chicken to serving plates and spoon the pan sauce generously over each piece. Garnish with additional fresh parsley and serve immediately.