Place popcorn and chopped pecans in a large bowl and set aside.
Combine brown sugar and cinnamon in a large glass bowl. Mix well. Add butter and corn syrup. Microwave on high for 30 seconds; stir to combine. Return to microwave and heat for 2 minutes. Remove and stir. Microwave for 2 more minutes. Stir in vanilla and baking soda. Mixture will foam. Pour caramel mixture over popcorn and pecans and stir till everything is well coated.
Line a jelly roll pan with a silicone baking liner, or use parchment paper. Pour popcorn onto the prepared pan. Place in oven and bake at 250° for 30 minutes, stirring every 10 minutes.
Melt almond bark according to package instructions. Drizzle over popcorn mixture. When almond bark is set and popcorn is cool, break into chunks. Enjoy!