In a blender, combine the bananas and melted dark chocolate. Blend until smooth and creamy.
Line a loaf pan with parchment paper for easy removal.
Sprinkle sliced strawberries and blueberries evenly across the bottom of the pan.
Pour the banana-chocolate blend over the berries, spreading evenly with a spatula.
Place in the freezer for 2–3 hours, or until firm.
Lift the fudge out using the parchment paper and slice into pieces. Thaw a little bit for kids.