Cut the chicken breasts thin and place them in a bowl with the buttermilk. Marinate for at least 30 mins and up to overnight.
Preheat the oven to 375 F. In a small bowl, mix together the Greek yogurt, ½ the Parmesan cheese, dried minced onion, garlic powder and dried parsley until well combined
Place the chicken breasts on a baking dish and spoon the mixture evenly on top of each chicken piece. Top with the rest of the Parmesan cheese and bake for 45 minutes until golden brown. For the last 5 minutes of cooking time, turn on the broiler to ensure the crust browns evenly.