Comebine sugar and evap. Milk in heavy saucepan. Bring to boil, stirring constantly. Reduce heat and simmer 6 minutes without stirring.

Remove mixture from heat and add chocolate, stirring until blended. Add butter and vanilla and stir. Refrigerate until mixture begins to thicken, about 30 minutes. Beat chocolate mixture kuntil thick and creamy. Fold in whipped cream. Chill until spreadable.

Makes 3-1/3 cups, enough to frost 1 9" 2 layer cake.