Preheat your oven to 350ºF. This will ensure the casserole bakes evenly and comes out perfectly golden. Lightly spray a 9×13-inch baking dish with cooking spray to prevent sticking. I always make sure to coat it well, as it helps with cleanup later.
Cook the spaghetti according to the package directions until al dente. Drain the pasta and set it aside. You want it to hold its shape, so don’t overcook!
In a large bowl, combine the cooked spaghetti, cottage cheese, cream cheese, and sour cream. Stir everything together until well mixed. The cream cheese should blend in smoothly, creating a creamy mixture that will coat the pasta.
Spread the pasta mixture into the bottom of your prepared pan. Make sure it’s evenly distributed as this will be the base of your casserole.
Now, take the cooked and chopped chicken and spread it evenly on top of the pasta mixture. This layer adds a heartiness that will truly satisfy.
Next, pour the Alfredo sauce over the chicken, making sure to cover it fully. This will help keep the chicken moist while it bakes.
Finally, sprinkle the parmesan cheese and mozzarella cheese on top. The mozzarella will melt beautifully, creating a cheesy, bubbly topping that’s hard to resist.
Bake the casserole, uncovered, in the preheated oven for 35 to 45 minutes. Keep an eye on it; the cheese should be melted and slightly golden on top, while the entire dish is heated through.
Once baked, remove from the oven and let it sit for a few minutes before serving. This allows everything to set a bit, making it easier to serve. Enjoy your Million Dollar Chicken Alfredo!