You will find this recipe on the Hershey's website -- my husband sent me searching about 6 months ago for the fudge his mother used to make using "the brown Hershey's can of cocoa"!

Prep time: 25 minutes
Start to finish: 3 hours, 20 minutes

Ingredients:3 c. sugar
2/3 c. Hershey's Cocoa
1/8 t. salt
1 1/2 c. milk
1/4 c. (1/2 stick) butter
1 t. vanilla extract

Line 8 or 9" square pan with foil, extending foil over edges of pan. Butter foil.

In heavy 4 qt. saucepan, stir together sugar, cocoa and salt; stir in milk. Cook over medium heat, stirring constantly, until mixture comes to a full rolling boil. Boil, without stirring, until mixture reaches 234 degrees on candy thermometer or until small amount of mixture dropped into very cold water, forms a soft ball which flattens when removed from water. (Don't rest bulb of thermometer on bottom of saucepan!)

Remove from heat. Add butter and vanilla. DO NOT STIR. Cool at room temperature until lukewarm (110 degrees). Beat with wooden spoon until fudge thickens and just begins to lose some of its gloss. Quickly spread into prepared pan; cool completely and cut into squares.