Cook and stir sugar, syrup, water and salt in sauce pan until boiling. Cook without stirring until hard ball stage on candy thermometer. Remove from heat.
Beat egg whites with mixer until stiff. Slowly pour hot mixture over egg whites while beating continuously.
Continue beating, scraping sides often until mixture begins to lose gloss. Add vanilla and beat until candy can be dropped by heaping teaspoonfuls on aluminum foil. Add chopped nuts.