01 - Preheat oven to 400°F. Lightly grease a 9x13-inch baking dish with cooking spray or butter.
02 - Pat chicken breasts dry with paper towels. Season both sides generously with salt and black pepper. Arrange seasoned chicken in the prepared baking dish in a single layer.
03 - In a medium bowl, whisk together Caesar dressing, sour cream (or Greek yogurt), grated Parmesan, minced garlic, Dijon mustard, and lemon juice until smooth and well combined.
04 - Spread the sauce evenly over each chicken breast, ensuring complete coverage on all exposed surfaces.
05 - Sprinkle shredded mozzarella and additional Parmesan cheese evenly over the sauced chicken breasts.
06 - Bake uncovered for 25-30 minutes until chicken reaches internal temperature of 165°F and cheese is golden brown and bubbling.
07 - Let chicken rest for 5 minutes before serving to allow juices to redistribute. Garnish with fresh chopped parsley if desired.