Pat chicken breasts dry and season evenly with lemon zest, pepper, and salt on both sides.

Heat olive oil in a large skillet over medium-high heat. Add chicken and sear 5–6 minutes per side, until golden and cooked through (internal temperature 165°F). Remove chicken and transfer to a plate; tent with foil.

Reduce heat to medium, add butter to skillet. Once melted, stir in garlic and sauté 30 seconds until fragrant.

Add lemon juice and chicken broth, scraping up any browned bits from the bottom. Simmer sauce for 2–3 minutes until slightly reduced.

Return chicken to skillet, spoon sauce over each piece, and cook 1–2 more minutes to warm through.

Transfer to serving platter, spoon remaining sauce over chicken, and sprinkle with chopped parsley if desired. Serve hot.