Start this recipe with the custard. Place the cream, milk, sugar and vanilla into a saucepan and heat up till almost boiling. In a large bowl, whisk together the corn flour, egg yolks and enough of the milk mixture to create a smooth consistency. When the milk mixture is hot enough, pour over the egg yolk mixture and whisk thoroughly. Pour the mixture back into the saucepan and bring to the boil stirring constantly. Remove off the heat and allow to cool down slightly. Meanwhile, immediately spread the cake slices with the strawberry jam and cut them into large squares. Place 1/3 into the base of the trifle bowl and drizzle over 2 tbsp limoncello liqueur. Spoon over 1/3 of the custard and spread out. Arrange 1 box of the raspberries on top. Repeat this process twice using the remaining ingredients. When ready, place into the fridge to chill for an hour or two before decorating the top with white chocolate scrolls and piped whipped cream rosettes.