Preheat oven according the cake mix instructions.
Mix the ingredients for the cake mix up according to the package.
Add 2 cups of grated apples to the mix.
Pour cake mix into cupcake liners and place in oven to bake.
When cupcakes have baked and cooled completely cut a circle out of the center of each cupcake, saving the top of the cake core.
Mix 1 cup of marshmallow fluff and 3 tablespoons of caramel sauce together.
Fill each cupcake with the caramel marshmallow fluff.
Place the top of the cake core over the fluff to cover the hole.
Mix the confectioner's sugar and butter together to make the frosting.
Add vanilla and caramel sauce to the frosting and mix thoroughly.
Add heavy cream 1 tablespoon at a time until the frosting is at the consistency you want.
Frost cupcakes and drizzle with extra caramel sauce.
Add a small apple slice to the top.