Prep the bananas: Peel the bananas and slice them in half lengthwise. Arrange them on a platter with the cut sides facing up.
Spread: Evenly spread the peanut butter over each banana half.
Blueberry layer: Arrange the blueberries in a row down two of the banana halves.
Blackberry layer: Halve the blackberries, then arrange them on the next two banana halves.
Raspberry layer: Finish by lining up the raspberries along the remaining banana halves.
