Combine butter, milk, chocolate, sugar, salt, and corn syrup in a medium saucepan. Place over low heat and cook, stirring constantly until sugar dissolves and mixture is well blended.

Bring to rolling boil and boil for 3 minutes. Remember that a rolling boil is one you can’t stir down. Remove from heat and add vanilla.

Cool completely then beat mixture until it is spreadable. I usually add a little bit of powdered sugar to help the “spread-ability”. If the frosting gets too stiff to spread, heat it a little and it will thin out.