60g caster sugar
280ml lactose free milk
1tsp vanilla extract
I've got to say up front, I am more than a little proud of myself here!
Start by beating your egg yolks together with the caster sugar, they should become slightly thickened. Next whisk in the cornflour.
Heat the milk and vanilla extract in a saucepan on a low heat until it just starts to boil. Remember to sir it regularly so it does not scald on the bottom. Apologies to the experts among us, but for the novices, milk does not boil like water. It should rise slightly in the pan but not bubble.
Pour half of the warm milk into the egg mixture. You need to try and pour this into the side of the bowl rather then directly onto the eggs. Also you must whisk constantly while adding the milk to avoid scrambling the eggs.
Now pour the egg/milk mix back into the saucepan containing the remaining milk. Whisk constantly. You will notice the mixture thicken. There is a fine line here. The first time I did this I did not allow the mixture to thicken enough and was left with a creme paissiere that was too runny and unusable. You can also leave it on the heat too long and the mixture will split and become unusable. Ideally you want a consistency you could pipe in a piping bag.
Once the mixture has thickened you need to take it off the heat and cool it rapidly so it does not continue cooking. I found the best way to do this is to put the saucepan into a large bowl of ice water. Once completely cooled store the creme patissiere in the fridge.