Keep popped corn hot and crisp in oven (300 - 325 F). Butter sides of saucepan. In it combine sugar, water, salt, corn syrup, and vinegar.
Cook to hard-stage (250 F). Add vanilla. Pour slowly over hot popped corn, mixing well to coat every kernel.
Press into balls (butter hands if necessary). Try not to burn your hands.
Serving Size: 8