Homemade Old fashioned Fudge

Here is the recipe! 3 cups Sugar 2/3 cup baking cocoa (I used Hershey's) 1/8 tsp salt 1-1/2 cups milk 1/4 cup butter 1 teaspoon vanilla extract Line a 8-9 inch pan with foil. cover foil with butter. Mix sugar, cocoa, and salt in heavy 4 quart sauce pan.Cook over medium heat, stir constantly, until mixture comes to full rolling boil. Then boil without stirring until thermometer reaches 234 degrees. You can test mixture by dropping small amount into ice cold water. It should form a small ball and flatten, esp when removed. (Don't allow thermometer to touch bottom of pan). Remove from heat, add butter and vanilla, and do not stir! Cool at room temperature to 110 degrees. Beat with wooden spoon until fudge thickens and is about to lose it's gloss (approx. 7 mins.). Quickly spread on prepared pan and cool completely. Store in tightly covered container at room temperature.