This is really good! I will never buy box mix again. I didn't have any elbow macaroni, I used rotini. I also shredded my cheese. We like our cheese freshly shredded. Oh I didn't have any cornstarch, flour works just fine.
Three Cheese Chicken Alfredo Bake - great make-ahead pasta dish. Elbow macaroni, alfredo sauce, sour cream, ricotta, garlic, chicken, eggs, parmesan and mozzarella cheese. SO good!! We make this at least once a month! Can freeze half for later. This is THE BEST pasta casserole we've ever eaten!!!