Coat 2 baking pans with coconut oil or if using roaster, spread inside pan with coconut oil. Spread popcorn on sheets. Preheat oven or roaster to 225 degrees F.
Place brown sugar, butter, salt, and corn syrup in medium saucepan on medium-high heat until it comes to a boil. Boil for about 5 minutes, stirring constantly.
Remove from heat; add vanilla and baking soda, stir until light and foamy, about a minute. Pour over popcorn; stirring well to coat.
Bake at 225 for 1 hour, stirring every 10-15 minutes. Allow to cool on pan. Store in airtight container.
