Line a 30 x 20cm tray with cling film.
Put the plums in a pan with 2 tbsp water
and 110g of the sugar. Cover with a lid and
stew over a medium heat for 10 mins
until soft. Allow to cool slightly, then blitz
with a hand blender. Pass through a sieve
to remove the plum skins. Allow to cool.
Put the remaining sugar in a pan with
150ml water, and dissolve over a low
heat. Boil for 5 mins or until the mixture
reaches 120C on a cooking thermometer.
To make the meringue base, whisk
the egg whites until stiff. With the
beaters running, carefully pour the
sugar mixture onto the egg white,
whisking until thick. In another bowl,
softly whip the cream, then gently fold
in the liqueur, plum pulp, biscuits and
the meringue. Pour into the tin, cover
with cling film and freeze for a few hrs
until set. To serve, remove from the
freezer 5 mins before scooping into balls.