Prepare the Alfredo Sauce In a large saucepan, melt the butter over medium heat. Add the heavy cream and garlic powder. Stir occasionally until the mixture simmers. Reduce heat to low and whisk in the Parmesan cheese until smooth and creamy. Season with salt and pepper to taste. Set aside.
Cook the Pasta Cook the jumbo pasta shells in a large pot of salted boiling water according to the package instructions until al dente. Drain the shells and rinse with cold water to prevent sticking. Set aside.
Make the Filling In a large mixing bowl, combine the shredded chicken, ricotta cheese, shredded mozzarella, Parmesan, egg, Italian seasoning, garlic powder, salt, and pepper. Mix until everything is well combined.
Stuff the Shells Preheat your oven to 350°F (175°C). Spread a thin layer of the Alfredo sauce on the bottom of a 9×13-inch baking dish. Stuff each shell with a generous amount of the chicken and cheese filling and place them in the dish, open side up.
Top and Bake Pour the remaining Alfredo sauce evenly over the stuffed shells. Sprinkle the shredded mozzarella cheese on top. Cover the dish with aluminum foil and bake for 25 minutes.
Finish and Serve Remove the foil and bake for an additional 10-15 minutes, or until the cheese on top is melted and bubbly. Let the dish cool slightly before serving. Garnish with fresh parsley if desired.
