Prepare the Cookies:

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

• In a large bowl, cream together the butter, granulated sugar, and dark brown sugar until smooth and fluffy.

• Beat in the egg and vanilla extract.

• In a separate bowl, whisk together the flour, baking powder, baking soda, instant espresso powder, and salt.

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

• Drop spoonfuls of dough onto the prepared baking sheet, spacing them about 2 inches apart.

• Bake for 10-12 minutes, or until the edges are golden brown. Allow cookies to cool on the baking sheet for a few minutes before transferring them to a wire rack to cool completely.

Prepare the Mascarpone Cream:

• In a medium bowl, whisk together mascarpone cheese, vanilla extract, confectioners sugar, and agave or honey until smooth and well combined.

• In a separate bowl, beat the heavy cream until stiff peaks form. Gently fold the whipped cream into the mascarpone mixture until combined.

Assemble the Cookies:

• Once the cookies have cooled, spread a generous layer of mascarpone cream on the bottom of one cookie and top it with another to form a sandwich.

• Dust the cookies with cocoa powder before serving.