In a 9x9 baking dish, combine popcorn, M&M's and peanuts. Set aside.

In a small pot, heat brown sugar, butter, corn syrup, pumpkin spice and salt over medium heat.

Stir continuously until mixture is well-combined and smooth.

Take pot off of heat and add baking soda.

Pour caramel over popcorn mixture and stir to coat evenly.

Put baking dish in oven at 250º for 15 minutes.

Take out of oven and stir mixture.

Place popcorn back in over for another 15 minutes.

Allow to cool on a rack, then enjoy!