1/2 cup white sugar
3 tablespoons unsweetened cocoa powder
1/4 cup cornstarch
1/8 teaspoon salt
2 3/4 cups milk
2 tablespoons butter, room temperature
1 teaspoon vanilla extract
In a saucepan, stir together sugar, cocoa, cornstarch and salt. Place over medium heat, and stir in milk. Bring to a boil, and cook, stirring constantly, until mixture thickens enough to coat the back of a metal spoon. Remove from heat, and stir in butter and vanilla. Let cool briefly, and serve warm, or chill in refrigerator until serving.