Place popped popcorn into a large bowl and salt to taste!
Put the marshmallow fluff/creme in a microwave-safe bowl and heat in the microwave until melted/easy to pour - heat 10-15 seconds at a time, until it's easy enough to pour over the popcorn. quickly stir in the cake mix powder
Quickly stir the cake mix powder into the melted marshmallow and drizzle over the popped popcorn and stir to coat popcorn.
Scatter out popped popcorn on a lined cookie sheet and sprinkle sprinkles all over while the marshmallow is still sticky.
Melt the white chocolate chips in the microwave 15-20 seconds at a time until fully melted, then drizzle over the popcorn.
Eat right away or store in an airtight container if there happens to be any left!