01 -
Lightly spray a 9x13-inch baking dish with non-stick cooking spray and set it aside.
02 -
In a large microwave-safe bowl, melt the butter. Add the marshmallows and stir to coat them in the butter. Microwave for 45 seconds, stir, then microwave again for another 45 seconds. Stir until smooth and melted.
03 -
Pour in the Fruity Pebbles and stir until the cereal is evenly coated with the marshmallow mixture.
04 -
Transfer the mixture to the prepared pan and press down firmly and evenly to spread it out.