01 - Preheat oven to 400°F. Lightly grease a 9x13-inch baking dish with cooking spray or a small amount of oil.
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, combine Caesar dressing, sour cream (or Greek yogurt), grated Parmesan, minced garlic, Dijon mustard, and lemon juice. Whisk until completely smooth and well incorporated.
04 - Spread the sauce evenly over each chicken breast, ensuring the meat is fully coated. Use a spatula or spoon to distribute sauce thickly across the surface.
05 - Sprinkle shredded mozzarella cheese and additional grated Parmesan evenly over the sauced chicken breasts.
06 - Bake uncovered for 25-30 minutes, or until chicken is cooked through (internal temperature reaches 165°F) and the cheese topping is golden brown and bubbling.
07 - Remove from oven and let chicken rest for 5 minutes before serving. Sprinkle with fresh chopped parsley for color and added freshness.