Season the Chicken
Pat chicken dry and season both sides with salt, pepper, and half the rosemary.
Sear the Chicken
In a large skillet, heat olive oil over medium-high heat. Add chicken and sear for 4–5 minutes per side until golden brown. Remove and set aside.
Make the Rosemary Butter Sauce
Reduce heat to medium. In the same skillet, melt the butter. Add garlic and remaining rosemary. Sauté for 30–60 seconds until fragrant. Stir in lemon juice and zest.
Return Chicken and Simmer
Place the chicken back into the skillet and spoon sauce over the top. Cover and cook on low for 5–7 minutes, or until chicken reaches an internal temp of 165°F.
Serve
Plate the chicken and drizzle with the rosemary butter sauce. Garnish with fresh rosemary sprigs and lemon slices, if desired.