AllRecipes.com with modifications
1 cup butter 1/2 teaspoon baking soda
2 cups brown sugar 1 teaspoon vanilla extract
1/2 cup corn syrup 5 quarts popped popcorn
1 teaspoon salt
Optionally: Almonds, Pecans & Chocolate for drizzling.
Preheat oven to 250 degrees F (95 degrees C). Place popcorn in a very large bowl or pot.
In a medium saucepan over medium heat, melt butter. Stir in brown sugar, corn syrup and salt. Bring to a boil, stirring constantly. Boil without stirring 4 minutes. Remove from heat and stir in soda and vanilla. Pour in a thin stream over popcorn, stirring to coat.
Place in two large shallow baking dishes and bake in preheated oven, stirring every 15 minutes, for 1 hour. Remove from oven and let cool completely before breaking into pieces Optionally: after the 2nd 15 minutes, add the nuts. When cool drizzle with melted chocolate