Preheat the oven to 350 degrees and grease 9x13 pan with cooking spray.
Dump the pie filling into the pan and spread into an even layer. Sprinkle cake mix over the pie filling. Then gently press it into the filling. Scatter the cold cubed butter over the cake mix.
Bake until bubbly and browned, about 30 minutes. Serve warm with vanilla ice cream.