Place the milk, glucose, milk powder, vanilla, salt & 60 grams of the caster sugar into a large saucepan.
Whisk to combine then place the saucepan over a low heat & leave to warm gently until steaming – don’t let it boil. Make sure to stir the milk regularly with a spatula.
Whilst the milk is heating up, place the egg yolks & remaining sugar into a mixing bowl & whisk to combine.
Once the milk is steaming hot, pour half of it into the yolks, whisking as you do so. Pour the now tempered yolks into the pan of milk.
Cook the custard over a low heat, stirring constantly with a rubber spatula until it is thick enough to coat the back of a spoon & has reached a temperature of 82°c/180°f. Once cooked, take the custard off the heat.A digital food probe comes in handy here! Next, add the mascarpone & marsala wine into a mixing bowl & whisk until smooth. Add into the warm custard & whisk to incorporate.
Give the custard a quick blitz with a stick blender then pass into a clean bowl, through a sieve. Leave to cool to room temperature, stirring regularly then cover the custard's surface with a piece of baking parchment & refrigerate overnight.