Preheat the oven to 350°F (175°C). Line a muffin pan with cupcake liners.

In a medium bowl, whisk together flour, cinnamon, baking powder, baking soda, and salt.

In a large bowl, cream together butter and sugar until light and fluffy.

Beat in eggs one at a time, then stir in vanilla extract.

Gradually add the dry ingredients to the wet ingredients, alternating with milk, beginning and ending with the dry ingredients. Mix until just combined.

Fill each cupcake liner with 2 tablespoons of batter.

Bake for 14-16 minutes, or until a toothpick inserted into the center comes out clean.

Combine cinnamon and sugar in a small bowl.

While the cupcakes are still warm, dip the tops in the cinnamon-sugar mixture.

Let the cupcakes cool completely.

For the filling, combine dulce de leche and sour cream in a small bowl. Mix well.

Transfer the filling to a piping bag.

Create a hole in the center of each cupcake using an apple corer.

Pipe the dulce de leche filling into the hole of each cupcake.

For the frosting, whisk heavy cream until stiff peaks form.

In another bowl, whisk together mascarpone cheese, cinnamon, and confectioners' sugar until smooth.

Gently fold the whipped cream into the mascarpone mixture until fully incorporated.

Frost the cupcakes and sprinkle with leftover cinnamon-sugar.