Beat the egg yolks and sugar for a few minutes until pale and slightly thickened. Whisk in the flours. Cut a vanilla pod in half lengthways and scrape put the seeds. Heat the milk in a saucepan with the vanilla seeds and the pod until it comes to a boil. Leave for 5 minutes to steep. Remove the pod (save this for infusing to sugar, it must dry out first though).
Whisk the milk into the egg mix. Pour the whole lot back into the pan, whisking all the time until thick and boiling. Take the pan off the heat and pour into a clean bowl and dot with a few small knobs of butter to stop a skin forming cover directly on the surface of the custard with a parchment disc. Leave to cool completely.
Take the strawberries and reserve 3-4 for decorating. Hull the remaining and then chop and mash with a fork. Add a little sugar if you feel it needs it. (bear in mind the sponge and custard are sweet)
Whip the cream until it’s slightly thickened. Loosen up the creme patisserie by whisking it, then fold and stir in 80ml cream to begin with, add a little more, if it's still too stiff.