01 - Preheat the oven to 400°F. Lightly coat a baking dish large enough to arrange chicken breasts in a single layer.
02 - Pat chicken breasts dry thoroughly with paper towels and place them evenly into the baking dish.
03 - In a mixing bowl, thoroughly whisk together Caesar dressing, sour cream, 1/2 cup grated Parmesan cheese, garlic powder, and black pepper until homogeneous.
04 - Evenly spread the prepared sauce over each chicken breast, ensuring full coverage.
05 - Distribute shredded mozzarella cheese and 2 tablespoons of grated Parmesan over the coated chicken breasts.
06 - Bake in the preheated oven for 25 to 30 minutes, or until chicken reaches an internal temperature of 165°F and the surface is golden and bubbly.
07 - Allow chicken to rest for 5 minutes outside of the oven. Sprinkle with chopped parsley prior to serving, if desired.