Cook sugar, water, salt, chocolate and corn syrup over low heat, stirring continually until sugar dissolves. Cover saucepan for 2 to 3 minutes to dissolve sugar crystals on side of the pan. Uncover and continue cooking to soft ball stage 236°F. Remove from heat, add butter and funky to lukewarm. Add vanilla and beat until spreading consistency. If frosting becomes stiff, add small amount of hot water.

A note about spreading consistency- the frosting goes from very liquid to fudgy firm quickly. I find it best to beat just until it starts to thicken and then start pouring over the cake. Pour at a rate where the icing drips down the side without pooling too much at the bottom.