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 both slices of bread. Lay one slice, buttered side down, into the pie iron.
Spread desired pie filling onto bread, and top with second slice, buttered side up.
Close pie iron over the sandwich and cook over hot coals until warm and crisp. Cooking time depends on how hot your coals are. Check after three minutes. If ready, flip the pie iron over and continue cooking the other side.
When sandwich is done, remove from fire and enjoy!