Here are a couple of recipes

Mazola No Stick corn -oil cooking spray
3 qt Freshly popped popcorn
1 c Karo light corn syrup
1 c Sugar
1/2 t Salt
1 t Vanilla

Spray large roasting pan with cooking spray. Add popped corn; keep
warm in 250 degree F. oven. In heavy 2-quart saucepan, combine corn
syrup, sugar and salt. Cook over medium heat, stirring constantly,
until mixture comes to a boil. Cook without stirring 10 minutes or
until temperature reaches 290 degrees F. on candy thermometer. Remove
from heat; stir in vanilla. Slowly pour over popcorn, stirring to
coat evenly.

Cool popcorn, stirring, just until mixture can be handled. Immediately
spray hands with cooking spray. Quickly shape popcorn into 3-inch
balls.

POPCORN BALLS

Here's a recipe from a really old BH&G cookbook. I hope it is the one you are after.
Popcorn Balls
5 quarts popped corn
2 c sugar
1 1/2 c water
1/3 tsp salt
1/2 c light corn sirup
1 tsp vinegar
1 tsp vanilla extract

keep popcorn hot and crisp in slow oven (330* to 325*.) cook sugar, water, salt, and corn sirup
to very hard-ball stage.(256*) add vinegar and vanilla extract; cook to light crack stage (270*)
slowly pour over popcorn; stir well to coat every kernel. press in balls. use fat on hands if
necessary. makes 20 balls.