Add the chopped chocolate, evaporated milk, granulated sugar, butter, and cocoa powder to a small saucepan set over medium heat. 

Cook, stirring often, until the chocolate has melted and the mixture is smooth, about 5 minutes. 

Remove the sauce from the heat and stir in the vanilla extract and kosher salt. 

Allow the fudge to cool to your desired temperature and serve. 

Transfer to an airtight container and store in the fridge for up to one week.