combine the sugar milk and salt in a heavy saucepan over med. heat,bring to a boil .cook over med. heat to 234-240 degrees on a candy thermometer,at soft ball stage.remove from heat .stir in butter and vanilla.while the butter melts stir in the chocolates.stir until mixture begins top get stiff.pour into a pan sprayed with cooking spray a 9/9 will work.let stay in the refrigerator until firm.it yields 1lb,this recipe can be doubled