3 c. sugar
2/3 c. cocoa
1/8 tsp. salt
1 1/2 c. milk
1/4 c. butter
1 tsp. vanilla

In heavy 4 quart saucepan, over medium heat, cook sugar, cocoa, salt, and milk to full boil, stirring constantly. Boil, without stirring, to 234 degrees on candy thermometer (or until syrup, when dropped into very cold water, forms a soft ball that flattens when removed from water). Bulb of thermometer should not rest on bottom of saucepan. Remove from heat. Add butter and vanilla. DO NOT STIR. Cool. Beat. Quickly spread in buttered pan.