Prepare Ingredients: Begin by gathering all your ingredients for the Fruity Pebbles Sushi. Grease your hands with a little butter to prevent sticking later, and set aside a large baking sheet lined with parchment paper for easy cleanup.

Melt Marshmallows: In a medium pot over low heat, add your marshmallows and stir continuously for about 4-5 minutes until they melt into a smooth, gooey consistency. Remove from heat when melted.

Mix with Cereal: Immediately add the Fruity Pebbles cereal into the melted marshmallow mixture. Stir gently for about 1-2 minutes until well coated.

Shape Sushi: Transfer the colorful mixture onto your prepared baking sheet. With greased hands, press and flatten the mixture into a rectangle, approximately ½ inch thick. Sprinkle optional fillings if desired.

Roll and Slice: Carefully lift one edge of the parchment paper to start rolling the sushi mixture into a tight log shape. Slice into bite-sized pieces resembling traditional sushi rolls.

Store: Place the sliced Fruity Pebbles Sushi in an airtight container at room temperature. Store in a single layer or use parchment paper between layers to maintain freshness.