In a saucepan, whisk together the sugar, cornstarch, and salt.

Gradually add the milk while whisking to combine.

Cook over medium heat, stirring constantly until the mixture thickens and comes to a boil.

Once boiling, continue to cook for 1-2 minutes, then remove from heat.

Stir in the butter and vanilla extract until fully incorporated.

Pour the pudding into serving bowls and let it cool to room temperature.

Refrigerate for at least 2 hours before serving.