225g/8oz plain flour, plus extra for dusting
100驳/3陆辞锄 caster sugar
40驳/1陆辞锄 cornflour
200g/7oz icing sugar
陆 tsp salt
1 vanilla pod, split down the middle and seeds scraped out
50g/2oz dark chocolate, melted
200g/7oz butter, chilled and cut into 1cm/陆in cubes
40驳/1陆辞锄 butter
4 free-range eggs, yolks only
500ml/18fl oz milk