Butter the inside of one 13x9x2-inch cake pan, then set the pan aside.
In a large stock-pot, melt the 5 tablespoons of butter over very low heat. (Whenever I make rice krispie bars, I use an 8-quart Teflon coated stock-pot.)
After the butter's melted in the pot, add the miniature marshmallows, and stir until the marshmallows have completely melted.
Remove pot from the heat, add the cereal, and stir until the cereal is evenly coated with the marshmallow mixture.
Press the marshmallow/cereal mixture into the buttered pan.
Let bars sit for 2-3 hours, before cutting them.
Note: The actual fruity flavored rice krispies cereal I used to make these bars were... Malt-O-Meal Fruity Dyno-Bites, which I purchased from Wal-Mart. I also subbed Malt-O-Meal Crispy Rice Cereal for the Kellogg's Rice Krispie Cereal as well.