Step 1

In a medium saucepan, gently whisk together the sugar, cornstarch and salt.  Pour in the milk and egg yolks; whisk to combine, and stir the together over medium heat.  Continue to whisk... it will look like not much is happening for 3 to 4 minutes... but soon it will be bubbling away!  Cook, stirring, while the mixture thickens.  Once it seems like it has a nice, thick texture for pudding- pull it off the heat and stir in the butter.

Step 2

Spoon the pudding into small glasses or dishes and chill for at least 2 hours.  Top with whipped cream before serving.