Pass the infused milk into another saucepan, through a sieve then add in 65g of the sugar, the glucose syrup, milk powder, cocoa powder & salt. Whisk to combine then set over a low heat & leave to get steaming hot (but not boiling).
In the meantime, place the egg yolks & remaining sugar into a mixing bowl then whisk to combine.
Once the milk is steaming, pour a third of it into the yolks, whisking constantly as you do so. This is called tempering the eggs.
Pour the now tempered yolks back into the saucepan of milk then cook the custard over a low heat until it reaches 82°c/180°f, making sure to stir constantly with a rubber spatula.
Once the custard is cooked, take it off the heat then stir in the double cream. Give the custard a quick blitz with a stick blender then pass into a container, through a sieve.
Let the custard cool, stirring occasionally then place a piece of baking paper onto the custard’s surface & refrigerate overnight.