Grease a 13 x 9 baking dish

Melt the butter in a large pot on the stove over low heat.

Then I add the marshmallows to the pot, stirring occasionally.

When marshmallows are fully melted add the fruity pebbles and stir until marshmallow and cereal is well mix.

Add mixture to the pan and press down to form a flat surface

Allow mixture to cool for at least 1 hour, cut into desired bar size.