Preheat oven to 375°F. Grease a 9x13 casserole dish or large baking dish. Place chicken breasts in an even layer in the dish.
In a small bowl, whisk together mayo, ½ cup parmesan cheese, minced garlic, salt and pepper.
Spread mixture over chicken breasts. Sprinkle the remaining 1 cup parmesan cheese over the top of the chicken.
Bake for 40 mins, or until an internal temperature on an instant-read meat thermometer reaches 165°F. Serve hot and garnish with parsley, if desired.
