Pasta casseroles are amazing because you can basically add any ingredient you want to them. If you'd like you could add mushrooms, spinach, zucchini, or other vegetables to this pasta bake. NOTE: The ingredients in the recipe below make just enough to fill a 12" cast iron skillet. Adding more to the recipe could cause it to boil over in the oven. If adding more ingredients, suggest halving the amount of vegan sausage or placing the skillet on a baking sheet to prevent spills.