Line a baking sheet with parchment paper, wax paper, or a silicone mat.

In a microwave-safe bowl, melt the milk chocolate chips in 30-second intervals, stirring between each, until smooth.

Spread the melted milk chocolate in an even layer (about 1/4″–1/2″ thick) on the lined sheet.

In another bowl, melt the white chocolate chips using 30-second then 15-second intervals.

Stir the melted white chocolate with marshmallow fluff until smooth and thick.

Drop dollops of the white chocolate mixture over the milk chocolate base.

Use a butter knife to swirl and marble the two chocolates together.

Sprinkle Golden Grahams cereal and marshmallow bits evenly on top, pressing gently to adhere.

Freeze for 30 minutes (or refrigerate for 1 hour) until fully set.

Break into pieces and serve!