In a medium bowl, whisk together flour, cocoa powder, salt, baking powder, and espresso powder. Set aside.

In a stand mixer, cream butter, brown sugar, and granulated sugar on medium speed until fluffy (3-4 minutes). Add egg and vanilla extract, and mix until combined.

On low speed, gradually add the flour mixture until fully incorporated. Form the dough into a disc, wrap in plastic, and refrigerate for 1-2 hours until firm.

After chilling, let the dough sit at room temperature for 5-10 minutes until pliable but not sticky. Roll the dough on a lightly floured surface to ⅛-inch thickness.

Cut out circles using a 3-inch biscuit cutter. Transfer to parchment-lined baking sheets and refrigerate for 30 minutes.

For the ice cream, let it soften slightly, then spread it in a plastic wrap-lined pan. Freeze for 4-5 hours until firm.

Cut out ice cream circles using the same biscuit cutter. Place an ice cream circle between two cookies to form a sandwich.

Wrap the assembled sandwiches in plastic wrap and aluminum foil. Freeze for 8 hours or overnight. Enjoy cold!