1 stick or cube of real butter (1 stick is 1/2 cup)
2 teaspoons vanilla
1/2 teaspoons baking soda
Almond Bark, or white chocolate chips, to drizzle over the top of popcorn (opt)
Preheat oven to 250 degrees.
Place popcorn and nuts if desired, in a large bowl and set aside. In large microwave safe bowl, measure your brown sugar, and salt. Chop butter into chunks and place on top of sugar mixture. Pour Karo syrup over the top of everything. Microwave on high for 30 seconds and then stir to combine. Return to microwave and heat for 2 minutes more. Remove and store and then return to microwave for 3 minutes more, until hot and bubbly. The butter will combine well with ingredients by now.
Remove from the microwave and add in vanilla, cinnamon and baking soda. Store to combine. The mixture will foam and rise up. Pour caramel mixture over popcorn and nuts and stir very well, until well coated.
Spread popcorn mixture onto parchment lined cookie sheet. Place in the oven and bake for 10 minutes stirring every 5 minutes. Popcorn will still be slightly chewy. Bake a bit longer for crunchy popcorn.
Melt chocolate if desired and drizzle over the top of the popcorn. Let cool until chocolate is set.