Preheat the oven to 350 degrees and line a cupcake tin. Lightly spray cupcake liners with nonstick spray.
In a medium bowl, beat together the cake mix, apple pie filling and four eggs. Beat until well combined, but do not beat so long that the apple pie pieces get pulverized - you want bite size pieces to remain.
Scoop about 3 tablespoons of batter into each cupcake liner. This should only fill them barely over halfway - if you add more the cupcakes may bake up over the sides of the liners. Depending on which size cake mix you use, you may have some extra batter left over.
Bake cupcakes about 18-20 minutes until tops are puffed and spring back when you touch them and a toothpick inserted in the center comes out clean. Cool cupcakes completely before frosting.
For the frosting, begin by placing the softened butter in a mixing bowl or bowl of a stand mixer and beating until light and fluffy. Then add the caramel topping and beat it into the butter until well incorporated, light and fluffy. Then gradually beat in powdered sugar, beating well, until your frosting gets to the consistency you prefer. The amount of powdered sugar you need will depend on how thick or runny your caramel topping is. I used Smucker's brand caramel and used just over 3 cups powdered sugar. If your frosting gets too thick to incorporate 3 full cups of powdered sugar add just a little milk as needed.
Frost the cupcakes, then drizzle with additional caramel topping if desired.