4-Ingredient Casserole

"Yep, that's right. 4-Ingredient Casserole really only has four ingredients. Well, honestly, it can have up to 5 ingredients if you're craving a little garden freshness from a layer of spinach. Otherwise, it's just bright tomato sauce, cheesy and tender ravioli, and melty mozzarella with a topping of sharp and nutty parmesan. 4-Ingredient Casserole impresses with its own simplicity, and it is sure to please the crowd! It's amazing what only 4 (or 5) ingredients can do!..."