Line a half sheet pan with a nonstick rubber mat. Place a Plexiglas frame 25cm / 10in by 38cm / 15in by .5 cm / .25 in inside the sheet pan. Place the sheet pan in the freezer.
Churn or pacotize the sorbet. Transfer the sorbet to the prepared frozen frame and spread out evenly using an offset spatula. Place in the freezer to harden.
Line a half sheet pan with a nonstick rubber mat and freeze.
Once the sorbet has hardened, flip it onto another nonstick rubber mat before cutting it. Place it back on the frozen sheet pan and peel off the top rubber mat. Using a 5-cm / 2-in square cutter, cut out the sorbet squares, dipping the square cutter in warm (not hot) water each time to get a clean cut.
Once the sorbet is cut, lift each square using a small offset spatula and transfer to the second prepared frozen sheet pan. If the uncut sorbet starts getting too soft, return it to the freezer. The sorbet is directly exposed to the freezer ventilation, and this might cause excessive hardening and ice crystal formation, so don’t let it sit in this condition for too long.
Wrap it after 20 minutes or transfer to an airtight container, which will make service much easier. Reserve frozen until needed.