Preheat oven to 400°F (200°C). Lightly grease a 9x13-inch baking dish with cooking spray or olive oil.
Pat chicken breasts completely dry with paper towels. Place each breast between two sheets of plastic wrap or parchment paper and gently pound to an even thickness of about ¾ inch using a meat mallet.
Season both sides of each chicken breast with salt, pepper, garlic powder, and paprika.
Drizzle olive oil in the prepared baking dish and place seasoned chicken breasts in the dish.
Spread softened Boursin cheese generously over the top of each chicken breast, coating the entire surface with about 2-3 tablespoons per breast.
In a small mixing bowl, combine panko breadcrumbs, Parmesan cheese, melted butter, fresh parsley, rosemary, thyme, garlic powder, salt, and pepper. Mix until the breadcrumbs are evenly coated with butter and herbs.
Generously press the herb breadcrumb mixture onto the Boursin-coated chicken breasts, creating an even, thick layer that covers the entire top surface.
Bake uncovered for 25-28 minutes, or until the chicken reaches an internal temperature of 165°F and the breadcrumb topping is golden brown and crispy.
If the crust needs more color, turn on the broiler for the last 1-2 minutes, watching carefully to prevent burning.
Remove from oven and let rest for 5 minutes before serving.
Garnish with additional fresh herbs and serve immediately.