Pour marshmallow mixture over the dry blueberries and cereal; mix well to combine.

Spray two 8 inch square pan or one 9x13 rectangular pan with cooking spray. Pour in cereal mixture. Let cereal cool and set up in pan for at least an hour.

Remove from pan and cut into bars or squares. Dip the bottom of each bar/square in melted white chocolate; place on parchment paper to allow chocolate to set. Store in an air tight container.