Preheat oven to 250 degrees F (120 degrees C).

Preheating ensures even baking and proper caramel setting.📌

Add 1 tablespoon of vegetable oil to a 4-quart saucepan and heat over high heat. When oil is hot, add 0.5 cup of unpopped popcorn. Keep pan moving constantly. When unpopped popcorn stops popping, remove from heat. Place popped corn in oven to keep warm. Repeat this process until all unpopped popcorn has been popped. Set aside.

Popping in batches prevents overcrowding and ensures most kernels pop. Keeping the pan moving helps prevent burning.📌

Melt butter in a medium saucepan, then stir in brown sugar, light corn syrup, and salt. Bring to a rolling boil, stirring constantly; boil without stirring for 5 minutes. Remove from heat.

Stirring initially prevents sticking, but boiling without stirring allows the caramel to reach the correct temperature for setting.📌

Stir baking soda, vanilla extract, peanuts, pecans, and almonds into the brown sugar mixture. Quickly pour the nut mixture over the warm popcorn and toss until well coated. Spread on greased cookie sheets.

Work quickly as the caramel will begin to set. Greasing the cookie sheets prevents sticking.📌