You can always add vegetables of your choice to make a casserole. Along with Broccoli, you can add other vegetables such as sweet potato, red bell pepper, yellow bell pepper, cauliflower, etc. to make it more healthy. But if you are looking to make a non-vegetarian casserole, then you can add Shrimp or Chicken. Even Turkey and Ham works great in this Casserole. You can add in Processed Cheese, Cheddar Cheese, Parmesan, Swiss, Monterey Jack, or any cheese that you have in hand.