Crush the cookies into fine crumbs, but not dust - let some small pieces remain.

Add the melted butter and mix into a smooth mass.

Add the boiled condensed milk and mix well again until you get a smooth, sticky mixture.

With damp hands, roll candies the size of a large walnut and coat each one in the chopped walnuts.

Chill the candies in the fridge for a couple of hours so they hold together and set. Enjoy!