Special equipment: a candy thermometer, 20 bamboo skewers and an insulated, stainless steel bowl
Place the popcorn and peanuts in an insulated stainless steel mixing bowl.
Combine the sugar
and vanilla in a 1-quart saucepan
fitted with a candy thermometer
. Bring to a boil and continue to boil until the mixture reaches 250 degrees F, about 10 minutes.
Remove from the heat and stir in the butter until incorporated. Add the baking soda and stir until well incorporated.
Pour the hot, finished mixture over the popcorn and peanuts and stir to incorporate.
Hand form twenty 3-ounce portions of the kettle corn onto the ends of 20 bamboo skewers and let cool.
Pour one half of the liquid nitrogen, if using, into the insulated, stainless steel bowl.
Holding the end of one of the skewers, dip the popcorn
into the liquid nitrogen and hold it there for 5 seconds before lifting it out. Repeat with the remaining skewers.