Mix vanilla custard powder with milk till smooth. Pour into a non stick pan and cook, stirring till thick. Crumble the cake into a bowl.
Add sugar to the custard and stir. Add chocolate, cream and whisk till well blended. Spread ? of the cake crumbs at the base of a serving bowl, pour half the custard over, spread ? of the cake crumbs, sprinkle half the chocolate chips.
Pour the remaining custard, sprinkle the remaining cake crumbs and remaining chocolate chips.
Cool down to room temperature and chill in the refrigerator.