Preheat your oven to 350°F (175°C) and line a baking sheet with parchment paper.

In a large mixing bowl, cream together the softened unsalted butter, granulated sugar, and brown sugar until light and fluffy.

Add the eggs, one at a time, mixing well after each addition, then stir in the vanilla extract.

In another bowl, whisk together the all-purpose flour, cocoa powder, baking powder, baking soda, and salt.

Gradually add the dry ingredients to the wet mixture, mixing until just combined.

Pour in the cooled brewed coffee and mix gently until the dough is smooth.

Drop spoonfuls of the dough onto the prepared baking sheet, spacing them about two inches apart.

Bake for 10 to 12 minutes or until the edges are set, but the centers remain soft.

Allow the cookies to cool completely on a wire rack.

In a medium bowl, beat together the mascarpone cheese, powdered sugar, and optional coffee liqueur until smooth.

Once the cookies are cool, spread a dollop of the mascarpone mixture on half of the cookies and top them with another cookie to create a sandwich.

Dust the tops with cocoa powder and garnish with chocolate shavings before serving.