Preheat oven to 300 degrees.
In a large, foil-lined baking pan, spread popcorn and cereal. Sprinkle peanuts on top; set aside.
In small saucepan, stir together brown sugar, corn syrup, butter, tamari sauce, cinnamon, ginger and cayenne, if desired, over medium heat. Cook and stir until butter is melted and mixture is blended. Pour over popcorn mixture and stir to coat.
Bake 30 minutes, stirring twice. Remove from oven and stir: allow to cool.
Break into pieces. Serve immediately or store in an airtight container.