Step 1

Cook sugar, corn syrup, and water in a 2-quart pot over low heat, stirring constantly, until sugar is dissolved. (On humid days, use 1 tablespoon less water.) Cook, without stirring, to 260 degrees on candy thermometer (or hard ball stage).

Step 2

Beat egg whites in 1-1/2-quart bowl until stiff peaks form. Continue to beat while pouring hot syrup in a thin stream into egg whites. Add vanilla; beat until mixture holds its shape and becomes slightly dull. (Mixture may become too stiff for electric mixer). Fold in nuts (if you choose).

Step 3

Drop from buttered spoon onto waxed paper. Let stand at room temperature, turning candy over once, until outside of candy is firm--at least 12 hours. Store in airtight container.