Preheat oven to 350 degrees F. Line a baking sheet with parchment paper, and place thawed pie crust directly on baking sheet. Brush the top with egg wash and sprinkle liberally with cinnamon sugar (sugar and cinnamon mixed together). Bake for about 15 to 20 minutes or until golden brown. Allow to cool, and then crumble with your hands.
In a blender, combine the ice cream, apple pie filling, most of the pie crust crumbs, and milk. Blend until smooth and thick. If it is too thick, add a splash more milk until desired consistency is reached. Garnish with a few crumbles of pie crust on top. Enjoy!