• Preheat the oven to 350°F. Line two baking sheets with parchment paper and set aside.
• In the bowl of a stand mixer fitted with the paddle attachment, combine the softened butter, granulated sugar, and brown sugar. Cream until smooth.
• Add the egg and vanilla. Mix well until fully combined.
• Add the flour, espresso powder, salt, and baking powder. Mix thoroughly, scraping down the sides often.
• On a lightly floured surface, roll the dough to about ¼ inch thickness. Use a 2-inch round cookie cutter to cut out as many rounds as possible. Reroll scraps, kneading well between each roll.
• In half the rounds, use a 1-inch star (or similar shape) cutter to remove the center of the cookie.
• Place all cut cookies on parchment and transfer to the freezer for 10 minutes.
• Bake in the preheated oven for 9 to 10 minutes, or until the centers are set. Transfer to a wire rack and cool completely before assembling.

For the filling:

• In the bowl of a stand mixer, beat the softened butter and cream cheese together until smooth with no lumps remaining.
• Add the powdered sugar, salt, and vanilla. Mix on low until combined, then scrape down the sides and beat on medium for about 2 minutes until smooth and fluffy.
• Spread a layer of frosting over the top of each solid cookie base.
• Top each with a star-cutout cookie, pressing gently to set.
• Dust with powdered sugar before serving.