Line a half sheet pan with a nonstick rubber mat. Place a 25cm / 10in by 38cm / 15in by 1.75cm / .68 in frame inside the sheet pan and place the sheet pan in the freezer.
Pacotize 2 beakers of the ice cream. Transfer the ice cream to the prepared frozen frame and spread out evenly using an offset spatula.
Harden in a freezer. Depending on the freezer, it can take as little as 30 minutes, but more time should be allowed if the freezer has a weak compressor.
Line another half sheet pan with a nonstick rubber mat and freeze.
Once the ice cream has hardened, flip the ice cream onto another nonstick rubber mat, place it back on the frozen sheet pan, and peel off the top nonstick rubber mat. Cut the ice cream into circles using a 7.5-cm / 3-in round cutter, dipping the cutter in warm (not hot) water each time to get a clean cut.
Once the ice cream is cut, lift each ice cream disk using a small offset spatula and transfer to the second frozen nonstick rubber mat–lined sheet pan. If the uncut ice cream starts getting too soft, return it to the freezer. The ice cream is directly exposed to the freezer ventilation, which might cause excessive hardening and ice crystal formation, so don’t let it sit in this condition for too long.
Once all the ice cream is cut and hardening in the freezer, place half the cookies on a sheet pan lined with parchment paper, with the rough side (the bottoms of the cookies) facing up. Transfer the ice cream disks to the top of the cookies, then top them with the other half of the cookies, smooth side up.
Return to the freezer to harden, then place them in an airtight container rather than on a sheet wrapped in plastic. This method of storage is more efficient for service.
Temper the cookies for 4 or 5 minutes before serving so they won’t be too hard to eat. Try wrapping the cookies with colored confection foil to make them even more special. If they are wrapped in different colors, it will be visually astounding.