Banana Pudding

Method

1. Whisk 25 g of caster sugar, 1.5 tsp of cornflour and a pinch of salt together in a small heavy saucepan so the starch is coated in sugar and cannot lump. Whisk in 120 ml of whole milk a little at a time until completely smooth, then whisk in 1 egg yolk.
2. Set the pan over medium-low heat and stir constantly with a whisk or wooden spoon, reaching into the corners, for 5-6 minutes. The custard will thicken suddenly; let it bubble gently for 30 seconds to cook out the starch, then pull it off the heat. It should coat the back of a spoon thickly and hold a line drawn through it.
3. Stir in 10 g of unsalted butter and 0.5 tsp of vanilla extract until the butter melts and the custard is glossy. Press a piece of clingfilm onto the surface if you are not layering straight away, so no skin forms.