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, 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 prepared sauce evenly over each chicken breast, ensuring the meat is completely covered. Use a spatula or spoon to distribute sauce uniformly.
05 - Sprinkle shredded mozzarella and additional grated Parmesan cheese over the sauced chicken, creating an even layer for the golden crust.
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 bubbly.
07 - Remove from oven and let the chicken rest for 5 minutes to allow juices to redistribute. Garnish with fresh chopped parsley before serving hot.