Preheat the pie iron over the hot coals of your campfire.
Remove carefully and lay on heat-resistant surface, being careful not to touch the hot iron. Butter or spray both inside sides of the pie iron.
Butter one side of a slice of bread and place it face down in the pie iron.
Spread some pizza sauce on top of the bread, then top with mozzarella cheese and any other desired toppings.
Some topping ideas include: 1) tomato and basil; 2) sausage and cheese; 3) pepperoni and mushroom; etc.
Add the second slice of bread, buttered on top, and close it up in the pie iron.
Cook over the campfire, turning it over occasionally to cook both sides. Check frequently.
When sandwich is fully cooked and bread is nicely toasted, remove from fire, serve, and enjoy!