Old Tyme Fudge

Preparation : Combine sugar and cocoa thoroughly. Add milk, stirring until mixture is smooth. Heat until mixture comes to a boil. Continue slow boil, stirring only occasionally to remove mixture from sides of pan. Cook to soft-ball stage (238 degrees). Remove from heat. Allow to cool for 5 minutes. Stir in butter and vanilla. Beat hard until fudge becomes very thick and starts to loose its gloss. Pour out into a buttered plate. When cooled, cut into squares. Store at room temperature.