Make the cupcake batter. In a large bowl, cream together the butter and sugar. Add the eggs one at a time. Stir in the vanilla and baking powder.
Add the flour and milk in batches, starting with flour and ending with flour. Stir until the batter is smooth and silky.
Fill paper-lined muffin tins with the batter 3/4 full.
Bake for 18 to 20 minutes. Allow to cool completely before decorating.
While the cupcakes are cooling, make the apple pie filling. Heat the butter in a large skillet over medium-high heat. Stir in the cinnamon, nutmeg and sugar. Cook until the mixture begins to bubble, about 1 minute.
Lower the heat to medium. Stir in the apples and salt. Cook and stir occasionally until the apples are tender, about 10 minutes. Remove from the heat and cool.
Assemble the cupcakes. Using a paring knife, cut out the middle of each cupcake using the coning method.
Spoon the apple mixture into each cupcake and drizzle caramel over all.