01 - Preheat the oven to 400°F. Lightly grease a 9x13-inch baking dish with olive oil or nonstick cooking spray.
02 - Pat the chicken breasts dry with paper towels. Rub both sides evenly with olive oil, then season generously with salt, black pepper, and garlic powder.
03 - In a medium mixing bowl, combine the ricotta cheese, Parmesan, mozzarella, parsley, dried basil, crushed red pepper flakes, and egg. Stir until all ingredients are thoroughly incorporated and the mixture is uniform.
04 - Arrange the seasoned chicken breasts in a single layer in the prepared baking dish. Divide the ricotta mixture evenly and spread it over the top of each breast, covering the surface completely.
05 - Spoon the marinara sauce over the ricotta-covered chicken breasts. Sprinkle the remaining mozzarella cheese evenly across the top.
06 - Bake uncovered on the center rack for 30 to 35 minutes, until the chicken reaches an internal temperature of 165°F and the cheese is golden and bubbling.
07 - Remove from the oven and let rest for 5 minutes to allow the juices to redistribute. Garnish with additional fresh parsley if desired and serve warm.