Continue cooking until all potatoes are soft. Wrap potatoes in paper towels and cool for 5 minutes. Split potatoes in half and scoop out flesh. Whip potatoes with butter, brown sugar and salt until smooth. Spoon pie filling over potatoes.
Place marshmallows in ring on top of pie filling.
Bake at 350 degrees 30-45 minutes until heated and marshmallows are lightly browned.