Preheat the Oven:
Preheat oven to 375°F (190°C). Lightly grease a baking dish with olive oil or butter.
Prepare the Ranch Mixture:
In a medium bowl, mix mayonnaise (or Greek yogurt), Parmesan cheese, ranch seasoning mix, salt, and pepper until creamy and smooth.
Coat the Chicken:
Pat the chicken breasts dry with paper towels. Place them in the prepared baking dish and spread the ranch mixture evenly over the top of each piece.
Bake Until Juicy:
Bake uncovered for 25–30 minutes, or until the chicken reaches an internal temperature of 165°F (75°C).
Optional Step – Broil for Color:
For a golden crust, switch to broil mode for the last 2 minutes.
Serve:
Remove from the oven, let rest for 5 minutes, and garnish with chopped parsley or chives. Serve warm with your favorite sides.