Prep the chicken. If the breasts are thick, slice them horizontally to create even cutlets, about 1/2 to 3/4 inch thick.
Pat dry with paper towels so the marinade adheres.
Make the marinade. In a bowl, whisk together the zest and juice of 1 lemon, olive oil, minced garlic, chopped herbs, 1 teaspoon salt, and 1/2 teaspoon pepper. Add Dijon or honey if using. The Dijon brings a gentle tang and helps emulsify; honey balances lemon acidity.
Marinate. Add the chicken to a resealable bag or shallow dish and pour the marinade over.
Toss to coat evenly. Refrigerate for 30 minutes to 2 hours. Avoid longer than 4 hours—too much acid can toughen the meat.
Choose your cooking method. You can bake, pan-sear, or grill.
Preheat now: Bake: 425°F (220°C)
Pan-sear: Medium-high heat with a slick of oil in a large skillet
Grill: Medium-high heat, clean and oil the grates
Cook the chicken. Bake: Arrange on a parchment-lined sheet. Bake 15–20 minutes, depending on thickness, until the internal temp reaches 165°F (74°C).
Pan-sear: Add chicken to the hot skillet. Cook 4–6 minutes per side, turning once, until golden and cooked through.
Grill: Grill 4–6 minutes per side, covered if possible, until nicely charred and done.
Rest and finish. Transfer to a plate and rest 5 minutes so the juices settle.
Squeeze the second lemon over the top and scatter a little extra chopped parsley. Taste and add a final pinch of salt if needed.
Serve. Pair with a high-fiber grain and a green vegetable for a balanced plate. Spoon any pan or baking juices over the chicken for extra zing.