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 completely 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 completely smooth and well combined.
04 - Spread the Caesar sauce evenly over each chicken breast, ensuring the meat is fully coated on all exposed surfaces.
05 - Sprinkle shredded mozzarella and additional grated Parmesan cheese evenly over the sauced chicken breasts.
06 - Bake uncovered for 25-30 minutes, or until chicken is completely cooked through and reaches an internal temperature of 165°F. The top should be golden brown and the sauce bubbly.
07 - Remove from oven and let the chicken rest for 5 minutes before serving. This allows the juices to redistribute. Garnish with chopped fresh parsley just before serving.