Put egg yolks, caster sugar and cornflour in a large bowl and whisk with a balloon whisk until combined. Gradually whisk the warm milk into the egg mixture. Transfer the custard to a saucepan and stir with a wooden spoon over a low heat until the mixture thickens (for about 8 minutes).
*Black plums - I use large black plums in this recipe as they are currently in season but you can use whichever type of plum that you like.
Lemon custard - makes approximately 460g of custard.