For the cookies

1. In a large mixing bowl, beat together the butter, sugar, salt, baking powder, and espresso powder until fluffy, about 3-5 minutes.
2. Beat in the egg and vanilla until combined, scraping down the bowl as necessary.  Add flour and cocoa powder and mix on low speed until dough comes together and no more flour is visible.
3. Turn the dough out onto a work surface and divide into 2 equal portions. Shape each portion into a ball, then flatten the balls into disks about 1/2 inch thick. Wrap in plastic wrap and chill until firm, about 30 minutes.
4. When ready to bake the cookies, heat the oven to 350 degrees F. Line two full-sheet sized baking sheets with parchment paper. Set aside.
5. On a work surface, lay down one large piece of wax paper. Remove one disk of dough from the refrigerator, unwrap it, and place on the wax paper. Lay another large piece of wax paper on top.  Roll out the dough (between the 2 sheets of wax paper) until it is about 1/8 inch thick or less.
6. Using a 2 1/2 inch and a 2 1/4 inch round cookie cutter, cut out rounds from the dough (see Notes). Slide a small offset spatula under the cut outs to lift them up and transfer them to the prepared baking sheets. Leave about 1/4 inch between the cookies.
7. Gather up and re-roll the scraps of dough and cut out more cookies. Repeat with the remaining disk of dough. If dough becomes too soft to work with, refrigerate the dough until it is firm again.
8. Bake the cookies for 10 minutes. Watch them closely so they don’t over bake. If you start to smell chocolate towards the end of the baking time, remove the cookies from the oven. Let the cookies cool in the pans for 2 minutes. Then transfer the cookies to a wire rack to cool completely before filling.

To make the sandwiches

1. Place a large storage container in the freezer so you can place the ice-cream sandwiches in the freezer as soon as they’re filled.
2. Pair up the cookies and lay them out on a work surface. Set aside.
3. Remove one carton of ice-cream from the freezer. Remove the lid and liner from the top of the carton. Using a pair of kitchen shears, snip down the side of the carton. Then peel away the carton. Place the block of ice-cream on its side on a cutting surface. Using a sharp knife, cut the block into 3 equal slices. It’s easiest to just press down on the ice-cream with the knife rather than using a slicing motion. Place the ice-cream slices between 3 cookie pairs and place completed sandwiches in the freezer. Repeat with remaining ice-cream and cookies.