Preheat the oven to 180°C.
Beat the butter and caster sugar in a bowl until pale and fluffy.
Beat in the eggs one by one until fully incorporated.
Fold in the flour, add a splash of milk if needed, then fold in the ginger.
Cook the chopped apples and sugar in a pan for 5 minutes until soft.
Boil the sauce ingredients in a pan while stirring until thick enough to coat a spoon.
Spoon sauce and apples into eight dariole moulds, then cover with the sponge mixture.
Place moulds in a roasting tray filled halfway with boiling water, cover with foil, and bake for 25 minutes.
Turn out the puddings and serve with remaining sauce and custard.