Line an 8-inch square baking dish with parchment paper and set aside.
In a medium saucepan, combine the sugar, cocoa powder, and salt.
Gradually add the milk while stirring constantly until the mixture is smooth.
Add the butter and stir until it melts and blends in.
Bring the mixture to a boil over medium heat, stirring constantly. Once it reaches a boil, stop stirring and let it boil for 2-3 minutes.
Remove the pan from the heat and stir in the vanilla extract.
Beat the mixture vigorously with a wooden spoon or hand mixer until it thickens and loses its shine.
Quickly pour the fudge into the prepared baking dish and smooth the top.
Let it cool at room temperature for at least 2 hours or until it’s firm to the touch.
Lift the fudge out of the pan using the parchment paper, cut it into small squares, and enjoy!
