Preheat the Oven: Preheat your oven to 375°F (190°C) and prepare a baking dish by lining it with parchment paper or greasing lightly with olive oil.
Prepare the Chicken: Pat the chicken breasts dry with paper towels to allow the seasoning and topping to adhere better. Season both sides of each breast with salt, pepper, garlic powder, and smoked paprika if using. For thicker breasts, consider slicing horizontally or pounding them for even cooking.
Mix the Creamy Topping: In a bowl, combine mayonnaise (or Greek yogurt), Parmesan cheese, onion powder, Dijon mustard, chopped parsley, and lemon juice. Mix thoroughly until the ingredients are well incorporated into a smooth, creamy mixture.
Coat the Chicken: Evenly spread the creamy mixture over the top of each chicken breast, ensuring full coverage.
Bake: Place the coated chicken breasts in the prepared baking dish. Bake in the preheated oven for 30–35 minutes, or until the internal temperature reaches 165°F (74°C) and the topping is lightly golden. For an extra-crispy finish, broil for an additional 2–3 minutes at the end.
Rest and Serve: Remove the chicken from the oven and let it rest for 5 minutes before slicing. Garnish with extra fresh herbs and lemon zest or wedges before serving.