For the coffee cookies: Whip together the melted butter and sugars then add the egg and vanilla.
Combine the dry ingredients in a separate bowl (flour, baking powder, baking soda, instant espresso powder, and salt).
Mix the dry ingredients into the wet.
Portion the cookie dough into balls. You can make 9 large ones or 11 smaller ones.
Place the cookie dough balls in the fridge to set.
For the mascarpone cream: Whip all the ingredients together until stiff peaks.
Bake the cookie dough balls on a parchment lined baking sheet at 355°F for 10-15 minutes.
Spread or pipe the mascarpone cream onto the fully cooled cookies.
Dust the tops with cocoa powder.
Keep refrigerated.
