Mrs. Dunmire's Fudge

2 C. gran. sugar
2-1/2 sq. Baker's choc.
2/3 c. milk
pinch salt
2 T. Karo corn syrup

Cook slowly until it forms a soft ball when dropped in cold water.  Remove from heat.  Add 2 T. butter without stirring and set aside to cool.  When lukewarm, and fairly cool, add vanilla & beat until creamy & ready to set.