Boil 600ml water with lemon zest, then simmer apricots, cranberries, and pineapple for 40 minutes before cooling for 4 hours.
Whisk egg yolks, cornflour, and sugar, then gradually add hot milk and cream while whisking.
Heat the custard mixture until thick, then remove from heat and allow to cool.
Sandwich trifle sponges with apricot jam and arrange them in a 3 litre dish with crumbled ratafias.
Mix 250ml of reserved fruit syrup with sherry and pour over the sponge and biscuits.
Layer the cooked fruit and cooled custard over the sponges, then chill in the fridge.
Beat double cream until soft peaks form, then spread half over the custard and scatter with almonds.
Pipe remaining cream around the edge and decorate with reserved sliced apricots and cranberries.