Place sugar and 3/4 cups water in another saucepan over medium heat
and bring to a boil.
Cook for a further 5 minutes for the mixture to become more syrupy.
Whisk together the milk, corn flour, egg yolks and vanilla extract.
Remove sugar water off the heat. Pour in the milk and yolk mixture and whisk. Place back over medium-high heat and bring to a boil, stirring.
Remove from heat and set aside to cool.