Wash the strawberries, remove the stems and cut the fruit into small pieces. Zest the oranges onto the strawberry, add the sugar and combine gently.
Break the sponge fingers into halves, place in a baking dish and drizzle the sherry on top.
Separate the eggs. Whisk the egg yolks and sugar together in a bowl. Slowly add the corn flour while whisking. Bring the milk and cream to the boil in a heavy bottomed pan. Pour the boiling liquid onto the egg mixture, return to the pan cook over a medium heat until the custard coats the back of a spoon. Allow to cool, transfer to a piping bag and refrigerate until ready to assemble the trifle.
For the chantilly cream: split the vanilla pod in half and scrape out the seeds. Add the sugar and vanilla seeds to the cream and whisk until thick. Spoon the cream into a piping bag and keep chilled until ready to assemble.
Line the base of your trifle dish with sherry soaked sponge fingers. Top with a layer of strawberries and then pipe on a layer of custard. Top with the vanilla cream to finish.
«Take care not to overcook the custard - you want it to coat the back of a spoon. Remove from the heat at this point and allow to cool thoroughly before assembling the trifle.»