01 - 
                Combine sugar, evaporated milk, butter and salt in medium saucepan. Heat over medium, stirring constantly until boiling.
              
              
              
                02 - 
                Stir in chocolate chips until melted and smooth.
              
              
              
                03 - 
                Remove from heat. Quickly stir in marshmallows, vanilla and optional nuts until marshmallows melt completely.
              
              
              
                04 - 
                Transfer to greased 8-inch square pan and smooth top.
              
              
              
                05 - 
                Cool at room temperature until firm before cutting into squares.