1In a medium saucepan, combine the sugar, cornstarch, and salt.
Gradually whisk in the milk until the mixture is smooth.
Place the saucepan over medium heat and cook, stirring constantly, until the mixture thickens and comes to a boil.
Once boiling, continue to cook for 1-2 minutes, stirring constantly, until the pudding is thickened.
Remove the saucepan from the heat and stir in the vanilla extract.
Pour the pudding into individual serving dishes or a large bowl.
Cover the surface of the pudding with plastic wrap to prevent a skin from forming.
Allow the pudding to cool to room temperature, then refrigerate for at least 2 hours before serving.