Combine sugar, cornstarch, and salt in a large bowl, and stir well. Combine cream and egg yolks, stirring well. Stir egg yolk mixture into sugar mixture. Gradually
add half of the hot milk to sugar mixture (if you go too fast it will get clumpy), stirring constantly with a whisk. Return hot milk mixture to pan, add maple syrup
for extra flavor yumminess if desired. Bring it almost to a boil again and keep stirring with a whisk. It should begin to thicken, then cook for one more minute. Remove from heat. Add butter (and vanilla extract
if that's what you're using), stirring until melted. Remove vanilla bean and discard.