Preheat your oven to 350°F (175°C) and line a muffin tin with cupcake liners.

In a large mixing bowl, whisk together the all-purpose flour, cocoa powder, baking powder, and granulated sugar until well combined.

In a separate bowl, whisk the eggs, milk, and vegetable oil together until smooth.

Gently fold the wet ingredients into the dry mixture using a spatula until combined.

Spoon the batter into the prepared liners, filling them about two-thirds full. Bake for 18-20 minutes.

Allow cupcakes to cool in the pan for about 5 minutes, then transfer to a wire rack to cool completely.

Whip together the mascarpone cheese and espresso until light and fluffy.

Once cooled, cut off the tops of the cupcakes and scoop out a small portion. Fill each with the mascarpone mixture.

Dust the filled cupcakes with cocoa powder before serving.