While melting in microwave measure cereal in a large bowl. Mix marshamallow and butter to combine.
Mix marshmallow and butter mixture with cereal and 1/2 of the other 10 oz. bag of mini marshmallows. Stir until incorporated. Put in greased 9X13 pan.
Refrigerate for 30 minutes before cutting.
Notes
-These rice krispie treats are the perfect amount of Fruity Pebbles. Not overly fruity! If you think it's not enough you could totally add more but I think it's just right!