Brown pancetta in a large, heavy pot over medium heat. Remove pancetta from the pot using a slotted spoon and drain on a paper towel.
Pour off all but 2 tablespoons of fat from the pot and return to the heat. Add popcorn and cover with the lid, venting it slightly. Cook popcorn, shaking the pot occasionally, until there are several seconds between popping kernels. Pour popcorn onto a cookie sheet that’s been lined with parchment paper or a silpat.
Preheat oven to 200 degrees.
Melt butter in a medium saucepan over medium heat. Add corn syrup and brown sugar and bring to a boil. Boil for one minute, then add salt, baking soda, and chile flakes. Remove from heat.
Sprinkle the reserved pancetta over the popcorn. Do the same with the peanuts. Carefully drizzle the hot caramel over the mixture and stir with a spatula to evenly coat the popcorn.
Bake for 40 minutes, stirring occasionally. Allow to cool on the pan, then break into chunks and store in an airtight container.