Begin by preheating your oven to 375°F (190°C). Lightly grease your baking dish to prevent sticking and set it aside.
In a skillet over medium heat, warm the olive oil. Add the breadcrumbs and toast, stirring frequently, until golden and fragrant—about 3 to 5 minutes. Remove from heat and set aside.
In a large mixing bowl, combine the cooked penne pasta, shredded chicken, marinara sauce, Alfredo sauce, garlic powder, Italian seasoning, salt, and pepper. Stir gently until everything is evenly coated.
Fold in half of the shredded mozzarella and half of the grated Parmesan cheese, reserving the rest for topping. This ensures cheesy goodness throughout the bake.
Pour the mixture into your prepared baking dish, spreading it out evenly. Sprinkle the remaining mozzarella and Parmesan cheeses over the top, then finish with the toasted breadcrumbs for a crunchy crust.
Place the dish in the oven and bake for 20 to 25 minutes, or until the cheese is melted, bubbly, and the breadcrumbs are golden brown. For an extra golden top, you can broil for an additional 2 minutes—just watch closely to avoid burning.
Let the Chicken Parmesan Alfredo Bake rest for about 5 minutes after removing it from the oven. This helps it set up for easier serving. Dish it out and enjoy the creamy, cheesy comfort!