Melt butter in a pan, over a low heat.
Add the marshmallows to the pan and keep stirring till the marshmallows melt completely.
Add the peanut butter to this and mix till blended well
Take the pan off the stove, set on the counter or table and add the Rice Krispies cereal and crumbled cookies to the marshmallow-peanut butter mix.
Once cooled, form into balls and serve.