There are so many ways to make this dish. The version I used for quick and easy meals was one I didn't even use a recipe for.
Brown some lean ground beef, Crumble, then brown some Italian sausage, sweet or hot.After the meats are browned, saute up some mushrooms in the drippings, toss in a bit of chopped green pepper. To this combination is added left over spaghetti sauce from dinner a couple of nights before. While the meat sauce is simmering, boil up some mostaccioli, when done, drain and mix it all together. Grease a deep casserole dish, pour in the whole mess and top with mozzarella, then either or a mixture of: parmesan, asiago, romano or provalone, whichever you like.
Now how simple is that?
Sometimes in a pinch, I'd use jarred sauce, and add a bit of garlic and spices to zip it up.