In a saucepan combine sugar, corn syrup, and vinegar. Attach a candy thermometer to the side of the saucepan making sure that the bulb is submerged but not touching the bottom. Cook the mixture over medium high heat, stirring until sugar dissolves. Continue to cook, uncovered, without stirring until the temperature registers 260 F, or alternatively, until a hard ball forms when a bit of the mixture is dropped in cold water. Remove pan from heat and stir in vanilla and 4 tablespoons butter.
Pour mixture over popcorn in a large buttered bowl and stir to coat. Use remaining butter to coat hands and shape the popcorn into balls and transfer to a parchment or wax paper-lined sheet pan. When the balls have hardened, individually wrap them in plastic wrap, colored plastic gift wrap or wax paper and secure ends with colorful ribbon.
Recipe courtesy of Gourmet Magazine