• Preheat the oven to 350°.

Cookies

• Combine the white cake mix, cornstarch, all purpose flour and instant espresso powder in a large bowl. Whisk the ingredients together to combine.
• In another bowl, add the softened butter, shortening, eggs and vanilla extract, mix using an electric mixer {I used a stand mixer with a paddle attachment}. Once combined add the dry mixture and continue to mix until you have a thick dough.
• Use a medium cookie scoop {or about 3 tablespoons} to measure out cookie dough onto a silicone mat {or parchment} lined baking sheet. Form the cookie dough mounds into round discs.
• Bake for 8-10 minutes or until the cookies are baked through but not over baked. Remove from the oven and allow them to cool completely on the baking sheet. Continue baking the 2nd and 3rd batch.

Mascarpone Frosting

• Once the cookies are cooled, add the mascarpone cheese to a medium bowl and mix using an electric mixer until smooth.  Add the powdered sugar, instant espresso powder and vanilla extract to the cheese and continue to mix until well combined.  Finally, add the heavy cream slowly and beat into the cheese mixture.  Once all of the heavy cream has been added, increase the speed to medium for a couple of minutes or until the frosting is light and fluffy.

Assembly

• Top each cookie with 1-2 tablespoons of frosting and spread out evenly.  Dust with cocoa powder and serve.