01 - Preheat the oven to 400°F. Lightly grease a baking dish large enough to accommodate the chicken breasts in a single layer.
02 - Pat the chicken breasts dry with paper towels and arrange them in the prepared baking dish.
03 - In a mixing bowl, whisk together Caesar dressing, sour cream, 1/2 cup grated Parmesan cheese, garlic powder, and black pepper until uniformly blended.
04 - Spread the prepared sauce evenly over each chicken breast to ensure full coverage.
05 - Sprinkle shredded mozzarella cheese and the remaining 2 tablespoons of Parmesan cheese evenly over the sauced chicken.
06 - Bake in the preheated oven for 25 to 30 minutes, or until the internal temperature of the chicken reaches 165°F and the cheese topping is golden and bubbling.
07 - Allow the chicken to rest for 5 minutes after baking. Garnish with chopped fresh parsley before plating, if desired.