In a large microwave safe bowl, microwave the butter, chocolate chips and peanut butter together at 30 second intervals, stirring after each, until the mixture is smooth.

Add the marshmallows to the bowl and microwave for one minute. Stir until smooth.

Pour in the cereals and carefully fold in until evenly combined.

Line a 9x9 pan with parchment paper. Press the cereal mixture in evenly. Allow to cool.

Remove the parchment paper and cut into 12 pieces. Spread the confectioners sugar on a plate and coat each square, tapping off the excess.