Preheat oven to 350 degrees F. Line a cupcake pan with paper liners.
In a large bowl cream butter and sugar until light and fluffy. Stir in milk, eggs, cinnamon, baking powder, and vanilla.
Gradually add flour a little at a time until just combined. Do not over mix.
Divide batter evenly between cupcake liners. Bake for 16-18 minutes or until a toothpick inserted in the center comes out clean. Cool in pan for 5 minutes before removing to wire racks to cool completely.
Once cool, cut a small circle out of the center of each cupcake.
For the Filling
In a medium saucepan melt butter over medium low heat.
Add apples, sugars, lemon juice, and cinnamon. Cook for 10-12 minutes or until apples are tender.
Stir in water and cornstarch, and cook until thickened.
Add ~½ tablespoon of apple pie filling to each cupcake. Replace cupcake "lid" that you cut out earlier.
For the Frosting
Cream butter until light and fluffy. Stir in vanilla and salt.
Gradually add powdered sugar a little at a time. Alternate with milk until you reach your desired consistency.
Spread or pipe onto cupcakes. Drizzle with caramel sauce if desired.