Spray inside of saucepan with non stick spray. Heat butter over stove until melted
Add bag of marshmallows and stir consistently until melted. At the same time measure out cereal and have it ready inside a large bowl.
Once marshmallows are melted, quickly pour mixture over cereal in a bowl and mix well immediately.
Spray square 8x8 pan with non stick spray. Spoon marshmallow mixture into pan and push down with a piece of parchment or wax paper until top is flat and even across the pan.
Break up chocolate bars into pcs and put into microwave at 30 second intervals stirring each time until melted and smooth (usually 1 minute total).
Pour over the top of your rice krispy treats and smooth until chocolate is the same thickness across the top.
Immediately sprinkle on mini marshmallows and sprinkle graham cracker crumbs on top of those.
Put in fridge for about an hour so chocolate can harden. Cut into squares.