01 - 
                Line an 8x8 pan with parchment paper.
              
              
              
                02 - 
                Heat chocolate, milk, butter, salt and vanilla in a pot over low heat. Stir until smooth, about 5-7 minutes. Don't rush or it'll burn.
              
              
              
                03 - 
                Take off heat and mix in black coloring until it looks like coal.
              
              
              
                04 - 
                Spread in pan. Add sprinkles if using.
              
              
              
                05 - 
                Let cool, then cover and chill at least 8 hours or overnight.
              
              
              
                06 - 
                Lift out with parchment and cut into 1-inch squares.