In a large pot, melt the butter until it begins to foam. Add the marshmallows and stir the mixture with a spatula constantly until all the marshmallows have melted.

Pour the marshmallow mixture into a large mixing bowl with the cereal and fold the ingredients gently until the cereal is evenly coated in the marshmallow mixture.

Spread the mixture into an 8x8 inch baking dish and allow the Fruity Pebbles treats to chill in the fridge for 3 hours.

Cut into squares, serve, and enjoy!