Hershey's Cocoa Fudge 
2/3 cup Hershey's Cocoa 
3 cups sugar 
1/8 tsp salt 
1 1/2 cups milk 
1/4 cup butter or margarine 
1 tsp vanilla 
Throughly combine dry ingredients in a heavy 4 qt. saucepan; stir in milk. Bring to a bubbly boil on medium heat, stirring constantly. Boil without stirring to 234 deg. F. (soft ball stage). 
Bulb of candy thermometer should not rest on bottom of saucepan. Remove from heat; add butter or margarine and vanilla. 
DO NOT STIR. 
Cool at room temperature to 110 deg. F. Beat until fudge thickens and looses some of its glass. QQuickly spread in a lightly buttered 88 to 9 inch square pan. Cool. Makes 3 dz. squares. 
This is from the Hershey Cocoa can from 1965. I kept the can till 1988 since this was never on new cans. Best fudge I made. It came out soft.  Jane cooked longer and made hard. 
Jackie Fuller