01 - Whisk olive oil, lemon juice, lemon zest, garlic, Dijon mustard, honey, oregano, salt, and pepper in a bowl until combined.
02 - Place chicken breasts in a shallow dish. Pour half the marinade over the chicken, turning to coat evenly. Reserve remaining marinade. Let sit for at least 10 minutes, up to 1 hour for more flavor.
03 - Heat 1 tablespoon butter in a large skillet over medium-high heat. Remove chicken from marinade and discard used marinade. Cook chicken 5–6 minutes per side until golden and internal temperature reaches 165°F.
04 - Transfer cooked chicken to a plate and tent with foil. Add reserved marinade and chicken broth to skillet. Bring to a simmer while scraping browned bits. Reduce sauce for 3–4 minutes.
05 - Whisk in remaining butter until melted. Return chicken to skillet, spoon sauce over, and simmer for 1 minute to warm through.
06 - Plate chicken, top with sauce, garnish with parsley and lemon slices, and serve immediately.