Preheat the oven to 375°F / 190°C and lightly grease a baking dish.
Brush the chicken breasts with olive oil, season with black pepper, and bake for 20 minutes until cooked to 165°F / 74°C.
Mix the Parmesan cheese, panko breadcrumbs, garlic powder, and melted butter in a bowl until combined.
Spread 2 tablespoons of ranch dressing over each cooked chicken breast.
Press the Parmesan mixture evenly over the ranch layer on each chicken breast.
Broil on high for 3 to 5 minutes until the Parmesan crust is golden and crisp, watching closely to prevent burning.
Rest for 3 minutes before serving to let the juices settle and the crust firm up.