Preheat the oven to 350°F (175°C).

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

Add the eggs one at a time, mixing well after each addition. Stir in the vanilla extract and dissolved coffee.

In a separate bowl, whisk together the flour and baking powder. Gradually add to the wet ingredients and mix until just combined. Fold in chocolate chips if using.

Using a cookie scoop, drop dough onto a baking sheet lined with parchment paper.

Bake for 12-15 minutes or until the edges are lightly golden. Allow to cool completely.

In a mixing bowl, beat the mascarpone cheese until smooth. Gradually add the powdered sugar and vanilla extract, mixing until combined.

In a separate bowl, whip the heavy cream until stiff peaks form. Gently fold into the mascarpone mixture until smooth.

Spread a generous layer of mascarpone frosting on the bottom of one cookie and sandwich it with another cookie.

Dust the tops with cocoa powder before serving.