Kids and adults alike will love munching on homemade caramel corn at a summer party.
Preheat oven to 350 degrees. Spread almonds in a single layer on a rimmed baking sheet, and toast until lightly golden and fragrant, about 10 minutes. Remove from oven; let cool completely. Generously butter two roasting pans, and set aside.
Combine butter, corn syrup, and brown sugar in a medium heavy-bottomed saucepan, and place over medium heat. Bring mixture to a boil, stirring constantly; stop stirring, and cook 3 minutes more. Add vanilla extract and reserved toasted almonds; continue cooking 1 minute more. Remove from heat, and stir in condensed milk and salt.
Place popcorn in a large bowl, and drizzle caramel mixture all over the top. Using a large well-buttered metal spoon, immediately toss to distribute evenly and combine. Divide between prepared pans.
Bake 7 minutes. Remove from oven, and stir mixture to allow it to cook evenly. Return to oven; bake 7 to 8 minutes more. Transfer to a wire rack to cool completely. Break apart clusters; serve.
Microwave popcorn does not work as well as traditional popcorn in this recipe, as it tends to crumble slightly when mixed with the caramel.