Preheat the oven to 225 degrees. Prepare a large metal bowl with cooking spray. Add popcorn and peanuts in the bowl and place in the oven to keep warm.
In a large saucepan combine brown sugar, corn syrup, coffee, butter and cayenne pepper. Cook over medium heat, stirring occasionally. Insert a candy thermometer and cook until mixture reaches the hard crack stage (290 degrees). Remove from heat and stir in vanilla extract.
Pour syrup over the popcorn and peanuts in a steady stream. Mix well until popcorn is completely coated.
Separate into small clusters using two buttered forks. You'll have to work quickly, as this sets fast!
Recipe by the modern barista at https://themodernbarista.com/index.php/2017/02/26/ethiopia-spicy-coffee-popcprn/