Ingredients
2/3 cup sugar
1/2 cup (1 stick) unsalted butter
1/4 cup light corn syrup
1 teaspoon pure vanilla extract
1 1/2 teaspoons salt
5 quarts plain popped popcorn
Preparation
Make caramel: In a medium saucepan over medium-high heat, combine sugar, butter, and corn syrup, stirring until melted and combined. Cover; cook 2 minutes to let steam wash down sides of pan. Remove lid; cook until mixture reaches 280 degrees on a candy thermometer, about 10 minutes. Remove from heat. Stir in vanilla and salt.
Place popcorn in a large bowl. Slowly pour half the caramel over popcorn, stirring to break up clumps. Drizzle in remaining caramel; stir until cooled and no longer sticky. Serve at room temperature.