Line two cookie pans with parchment paper; set aside. In medium saucepan, combine sugar, corn syrup, water and salt. Cook over medium heat, stirring until sugar is dissolved. (Do not stir mixture once sugar has dissolved.) Use pastry brush dipped in water to wash sugar crystals down sides of saucepan. Secure Candy Thermometer on side of saucepan. Continue cooking, without stirring, until thermometer registers 250°F (about 15 minutes).
Meanwhile, in large bowl, beat egg whites to stiff peaks with electric mixer. Once sugar syrup mixture reaches 250°F, remove from heat. Gradually add sugar syrup (in very thin stream) to egg whites while beating at high speed. Add vanilla extract. Continue beating at high speed until mixture begins to cool, thicken and mixture loses its gloss (about 5 to 8 minutes). Add pecans while beating.
Working quickly, drop rounded teaspoons of mixture onto parchment paper; immediately top with pecan half. Cool completely. Store candies in airtight container up to 2 weeks.
Cook's Tips: Humidity will affect making this candy. Avoid hot, humid or rainy days.
Use room temperature egg whites to achieve best volume.
Gift Giving Tip: Wrap candy in Clear Treat Bags and secure tightly; store filled treat bags in airtight container at room temperature.