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 to remove excess moisture. Season both sides generously with salt and black pepper. Arrange the seasoned chicken in a single layer in the prepared baking dish.
03 - In a medium bowl, combine creamy Caesar dressing, sour cream (or Greek yogurt), grated Parmesan cheese, minced garlic, Dijon mustard, and lemon juice. Whisk vigorously until completely smooth and well incorporated.
04 - Spread the sauce mixture evenly over each chicken breast, using a spoon or spatula to ensure full coverage. The sauce should be thick enough to cling to the chicken.
05 - Sprinkle shredded mozzarella cheese evenly over the sauced chicken, followed by the additional grated Parmesan cheese for a flavorful, golden crust.
06 - Bake uncovered for 25-30 minutes until chicken is fully cooked (internal temperature reaches 165°F) and the cheese topping is golden brown and bubbly. Avoid overbaking to prevent dry chicken.
07 - Remove from oven and let the chicken rest for 5 minutes to allow juices to redistribute. Garnish with chopped fresh parsley just before serving for a pop of color and freshness.