Preheat your oven to 375°F (190°C). Lightly grease a 9x13 inch baking dish or line it with foil for easier cleanup.
Pat the chicken breasts dry with a paper towel and place them evenly in the baking dish.
In a mixing bowi, combine the sour cream, mayonnaise, garlic powder, onion powder, paprika, salt, pepper, and Parmesan cheese (if using). Mix until smooth and well combined.
Spoon the creamy mixture evenly over the top of each chicken breast. Use the back of a spoon or spatula to spread it out.
Bake uncovered for 30-40 minutes, or until the chicken is cooked through (internal temp should reach 165°F/ 74°C) and the top is golden and bubbly.
For extra golden color, turn on the broiler for the last 2-3 minutes-watch closely to avoid burning.
Sprinkle freshly chopped parsley over the top and serve hot with your favorite sides like steamed veggies, mashed potatoes, or a fresh salad.
