Bring a large pot of salted water to a boil. Add the jumbo pasta shells and cook according to package directions until al dente, usually around 10-12 minutes. Drain carefully in a colander and rinse with cold water to stop the cooking process and prevent sticking. Set aside.
In a large mixing bowl, combine the shredded chicken, ricotta cheese, 1/2 cup of the grated Parmesan cheese, 1 cup of shredded mozzarella, Italian seasoning, salt, and pepper. Mix everything until nicely blended. This filling will be creamy and flavorful, perfect for stuffing into the pasta shells.
In a medium skillet over medium heat, melt the butter. Add the minced garlic and sauté for about 1 minute until fragrant but not browned. Slowly pour in the heavy cream, stirring continuously. Let it simmer gently for 5-7 minutes, allowing it to thicken slightly. Stir in the remaining Parmesan cheese and season with salt and pepper to taste. Remove from heat once the sauce is smooth and creamy.
Using a spoon or spatula, carefully fill each cooked jumbo shell with the chicken and cheese mixture. Be generous but avoid overstuffing to prevent shells from breaking. Place each stuffed shell seam side up in the prepared baking dish.
Pour the creamy Alfredo sauce evenly over the stuffed shells in the baking dish. Sprinkle the remaining 1/2 cup of shredded mozzarella over the top for a golden, bubbly finish. Cover the dish with foil and bake in a preheated 350°F (175°C) oven for 25 minutes. Remove the foil during the last 5 minutes to allow the cheese to brown beautifully.
Once out of the oven, let the shells cool for a few minutes. Sprinkle freshly chopped parsley on top for a burst of color and fresh flavor. Serve warm and enjoy the creamy, cheesy goodness!
