Pre heat oven to 350 degrees. In a 9x13 baking dish add 2 cans of apple pie filling and spread evenly. Sprinkle the box of cake mix evenly over the top of the apple pie filling. Cut the butter into thin slices and place the pieces evenly on top. Sprinkle the cinnamon sugar on top.
Bake at 350 degrees for 45-55 minutes until bubbly and light golden brown. Serve warm with vanilla ice cream and enjoy!