Pop your popcorn.
In a large pot, melt your butter over medium high heat.
Add in your marshmallows and your peanut butter and stir often until melted and creamy.
Pour your peanut butter marshmallow mixture over your popcorn in a large bowl and stir to fully coat the popcorn.
Mix in about 1 cup of your chopped Butterfinger pieces.
Spread your popcorn onto a cookie sheet lined with parchment paper.
Melt your chocolate chips in the microwave for about 45 seconds and stir until creamy and chocolate chips are all melted.
Drizzle chocolate over the top of your popcorn.
Sprinkle remaining 1/2 cup of Butterfinger pieces over the top of your popcorn.
Allow to set until your chocolate is hardened.