Lightly grease and line the 8x8 pan with parchment.

Add the granulated sugar, corn syrup, cocoa powder, chocolate, salt, and half and half in a heavy bottomed pot. Place it over medium heat and let it come to a simmer. Stir gently to make sure the sugar has dissolved. Let the sugar continue to cook until it reaches 235F, softball stage.

Turn off the heat and let it sit untouched until it reaches 110F. Start to stir and agitate the sugar to start crystalizing the sugar. The mixture will start cooling down and thickening. Once it gets thick and it starts losing it's sheen, pour it into the prepared pan and smooth.

Let it set for at least 2 hours or more. Cut the fudge into small squares.