Homemade Chocolate Pudding

In a saucepan, combine sugar, cocoa powder, salt, and cornstarch. Mix well. Add in cold milk, whisk until combined.

Turn heat to medium, stirring constantly until mixture reaches a boil*.

As soon as the pudding has thickened, remove from the heat and stir in butter and vanilla.

Allow mixture to cool completely, stirring occasionally to avoid a skin forming on the pudding.

Serve chilled or warm.