In medium saucepan combine sugar, cocoa, cornstarch and salt with a whisk.
Add milk and continue to whisk. Heat to simmer over medium heat.
Cook for 1-2 minutes until thick and bubbly.
Remove from heat - add vanilla and butter
Pour into your favorite dessert glass and chill throughly.
Stir together sugar, cocoa, cornstarch and salt in large microwave-safe bowl; gradually stir in milk.
Microwave at HIGH (100%) 7 to 10 minutes or until mixture comes to full boil, stirring every few minutes.
Stir in butter and vanilla. Pour into dishes to cool.
