Step 1

Line a baking sheet with waxed paper or parchment paper.

Step 2

In a heatproof bowl set over a pan of barely simmering water, combine the white chocolate chips, peanut butter, and cocoa butter. Stir until melted and smooth.

Step 3

Remove the bowl from heat and let sit 10 minutes to cool, then stir in the cereal and chopped marshmallows until well coated.

Step 4

Drop by the spoonful onto the prepared baking sheet and sprinkle with a few mini chocolate chips or sprinkles, if using.

Step 5

Refrigerate until set, about 1 hour.