Mix raspberries, orange juice, zest, Aperol, and sugar in a bowl.
Let thaw, blend into a pulp, sieve, and freeze in a box, stirring hourly. Pack into moulds and refreeze.
Freezing
Slice the cake into 1cm thick pieces. Cut circles slightly larger than the base of the moulds and set aside.
For the meringue, heat sugar, liquid glucose, and egg whites in a bowl over simmering water until sugar dissolves.
Whisk off heat until thick, fluffy, and spreadable. Add icing sugar.
Preheat the oven to 200°C (fan 180°C/gas mark 6).
Spread raspberry jam on cake circles.
Unmould frozen raspberry mix onto the sponge, flat-side down.
Pipe meringue over the raspberry dome from base to top.
Brown with a blow torch or bake for 3-4 minutes.
Serve immediately.