2 c. granulated sugar
1/2 c. evaporated milk
1/2 c. water
1/4 c. cocoa
1 tsp. butter
1 tsp. vanilla

Mix sugar and cocoa together until well blended. Add milk and water. Cook over medium heat until (stirring constantly) mixture comes to a full rolling boil. Cook until a drop from spoon forms a soft ball when dropped into cold water. (This is very important.) Remove from heat and set pan in cold water.

To the mixture add the butter and vanilla, stirring just until blended. Do not stir any more until cool (this is to prevent graininess). Now stir mixture until it begins to lose the glossy look and becomes thick. Turn onto a buttered pan and score while yet a little soft.