combine sugar, milk salt in heavy sauce pan over medium heat, bring to a boil. cook over medium heat to 234 to 240°F on a candy thermometer, soft-ball stage. remove from heat, stir in butter and vanilla. while butter melts stir in peanut butter and chocolate.stir mixture until it stiffings, pour into a buttered or cooking spray 9-9 inch baking dish. let stand in fridge until firm. makes 1pound