Traditional Irish Sherry Trifle

450g approx. homemade sponge cake or trifle sponges

225g good quality raspberry jam

For the custard:

5 eggs

1¼ tbsp caster sugar 

½ tsp pure vanilla extract 

750ml milk 

150-175ml best quality sweet or medium sherry 

To garnish:

600ml whipped cream 

fresh raspberries and cranberries