Took this idea from a taste of home recipe for caramel apple cupcakes. Most of the reviews said the caramel slid off the cupcakes by the next day, so I found a recipe for caramel frosting instead.
Use a box of spice cake mix, add finely diced green apples and bake as directed. Top with caramel frosting and add a super thin slice of green apple/chopped nuts to top as a garnish. I'm also trying to figure out if I could add a small caramel to the center and have it be a surprise inside. The cupcakes pictured in the original recipe had a stick coming out of the top as well, but no apple slice.
3/4 cup packed brown sugar
1/3 cup butter, cubed
1/4 cup 2% milk
1-1/2 cups confectioners' sugar
In a small heavy saucepan, combine the brown sugar, butter, milk and salt. Cook and stir over low heat until sugar is dissolved.
Increase heat to medium. Do not stir. Cook for 3-6 minutes or until bubbles form in center and syrup turns amber brown. Remove from the heat; transfer to a small bowl. Cool to room temperature. Beat in the confectioner's sugar until dissolved like a frosting.