Preheat oven to 250 degrees.
Place a silpat mat over each of the two baking sheets.
Pop the popcorn according to package directions. Spread a single layer of popcorn and peanuts over each baking sheet, dividing evenly. Set aside.
In a heavy bottom saucepan, combine brown sugar, butter, and corn syrup. Cook over medium heat for roughly 7 minutes, or until mixture comes to a boil.
Continue boiling for 2 minutes.
Remove pan from heat and stir in baking soda. Allow to cool slightly Don't let it get too cool or it will start getting hard!
Pour caramel mixture over popcorn and nuts and stir well so that the popcorn is coated.
Bake for 60 minutes, stirring every 15 minutes.
Remove from oven. Allow to cool completely.
Once cooled, melt chocolate chips with shortening in a double boiler. To do this, fill a sauce pan 1/3 of the way with water. Cover with a bowl and add chocolate and shortening. Stir continuously until melted.
Using a fork, generously drizzle chocolate over the popcorn and peanuts, and let stand 3-4 hours until chocolate is set. Break into pieces and enjoy. Store leftovers in an airtight container in a cool place.