How to freeze: follow the directions all the way through until you bake it the entire casserole. Leave the mozzarella off the top until you're ready to bake it one last time right before you eat it to avoid it getting soggy. Store in the freezer for up to 3 months. You can bake any leftovers by covering tightly as well. When you're ready to heat it, remove the lid from the tin, add the mozzarella, then bake at 375°F for 40-50 minutes or until it's warm all the way through.