1. Preheat the oven to 350 deg. F (175 deg. C)  Line a couple baking sheets with parchment and set aside.
2. In the bowl of a stand mixer, combine the softened butter, sugar and brown sugar.  Cream until smooth with the paddle attachment.
3. Add in the egg and vanilla.  Mix well.
4. Add in the flour, espresso powder, salt and baking powder.  Mix thoroughly, scraping down the sides often.
5. On a lightly floured work surface, roll out the dough to about ¼ inch thickness.  Use a 2 inch round cookie cutter to cut out as many rounds as possible.  Reroll the scraps as many times as you can, kneading well between each roll.
6. In half of the round cutouts, use a one inch star (or similar shape) cookie cutter to remove the center of the cookie.
7. Place the cookie rounds on a piece of parchment and transfer to the freezer for about 10 minutes.
8. Bake in the preheated oven for 9-10 minutes or until the centers are set.
9. Allow to cool completely before assembling.
10. For the frosting filling – in the bowl of a stand mixer, combine the softened butter and cream cheese.  Mix well, until there are no clumps and the mixture is smooth.
11. Add in the powdered sugar, salt and vanilla.  Mix on low until combined.  Scrape down the sides and bump up the speed to medium for about 2 minutes or until the frosting is smooth and fluffy.
12. Once the cookies are completely cool, spread a layer of frosting over the top of the solid cookie.
13. Top with the cookie with the center removed.
14. Sprinkle with a dusting of powdered sugar.

Storage:  Cookies should be stored in an airtight container in the fridge for up to 3 days.