Melt butter and let it cool. Combine melted butter with granulated and brown sugars until smooth.

Add egg and vanilla extract. Mix until well incorporated.

In a separate bowl, whisk together flour, baking powder, baking soda, espresso powder, and salt. Combine with wet ingredients.

Roll dough into balls, chill for 30 minutes.

Preheat oven to 180ºC (355ºF). Bake cookies for 10-11 minutes until edges are golden.

Whip mascarpone cheese, vanilla extract, confectioners sugar, agave, and heavy cream until stiff peaks form.

Pipe mascarpone cream onto cooled cookies and dust with cocoa powder before serving.