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

In a large mixing bowl, combine all-purpose flour, cocoa powder, baking powder, and granulated sugar and whisk together.

In another bowl, whisk together large eggs, milk, and vegetable oil until smooth.

Pour the wet mixture into the dry ingredients, stirring gently until just combined.

Fill cupcake liners about two-thirds full with batter and bake for 18-20 minutes.

Cool the cupcakes on a wire rack for 10 minutes before carefully removing them from the tin.

Whip together mascarpone cheese and espresso until fluffy.

Once cupcakes are cooled, cut off the tops and hollow out a small section. Fill with mascarpone mixture, then replace the tops.

Dust the tops of cupcakes with cocoa powder before serving.