Spray a 9x13 inch baking dish with cooking spray. Then toss the apples, brown sugar, apple pie spice, and salt together. Pour the cake mix on top of the apple mixture. Then pour the melted butter over the top of the cake mix.
Bake until the top of the cake is golden brown (about 50 minutes).
Serve warm and top with caramel sauce, pecans, and vanilla ice cream.