1 1/3 cups white sugar
2 tablespoons butter, melted
4 cups milk
1 tablespoon vanilla extract
1/2 cup cocoa powder
1/3 cup heavy cream
1 tablespoon margarine
In a large saucepan, dissolve sugars in melted butter or margarine. Stir constantly until sugar dissolves. Place over low heat, stirring constantly until sugar is completely dissolved. Bring to a rapid boil, stirring constantly until mixture thickens. Remove from heat. Mix cream or margarine into sides of pan, stirring constantly. Let cool. Spread over bottom of pan.
Pour cream or margarine into center of frosting. Spread over sides of each cake layer, covering almost entirely. Cover top and bottom of cake with frosting. Cover with straw.