Make the base following the modern ice cream method. The instant coffee is added just after the yolks.
Once the base has cooled, let it age for at least 4 hours before churning.
Meanwhile, put a sheet of flexible silicone half-domes that measure 5cm/2in base diameter by 4cm/1.5in high on a sheet pan and then freeze.
Churn the base and pour it into a piping bag. Pipe the churned ice cream into the prepared molds and even out the top with an offset spatula. Reserve frozen, keeping the exposed surface well covered to prevent freezer damage.
You may melt these domes down if they are frozen for more than 5 days and then re-churn them.