Line a 9X13 baking pan with foil or parchment paper and then spray with a non stick cooking spray.
Place the condensed milk and chocolate in a microwave safe bowl.
Heat in 30 second intervals in the microwave, stirring after each interval until the mixture is melted and well combined. Mine took approximately 90 seconds.
Stir in the peanuts and miniature marshmallows.
Pour the mixture into the prepared pan. Refrigerate until firm.
Then carefully lift the foil out of the pan and cut into pieces