Line a standard 8x4-inch loaf pan with waxed paper, leaving some overhang to lift the loaf out later. Lightly spray with nonstick cooking spray.
In a microwave-safe bowl, melt the chopped semisweet chocolate in 30-second intervals, stirring well between each, until smooth. Set aside to cool slightly.
In a medium bowl, mash the ripe bananas until smooth but slightly chunky.
Add the creamy peanut butter to the mashed bananas and stir until well combined.
Gently fold the whipped heavy cream into the peanut butter and banana mixture until just incorporated, maintaining the airy texture.
Pour half of the banana-peanut cream mixture into the prepared loaf pan and spread evenly.
Pour a layer of melted chocolate over the cream layer, then sprinkle half of the chopped roasted salted peanuts evenly on top.
Add the remaining banana-peanut cream mixture as the next layer, smoothing gently.
Top with the remaining melted chocolate and sprinkle the rest of the chopped peanuts evenly over the top.
Cover the loaf securely with plastic wrap or foil and freeze for at least 4 hours or until completely firm.
To serve, lift the loaf out using the waxed paper overhang. Slice with a warm knife and enjoy immediately as a frozen, creamy dessert.