01 - Line a rimmed baking sheet with parchment paper and set aside.
02 - Peel the bananas and cut into ΒΌ-inch thick rounds. Arrange the slices in a single, slightly overlapping layer on the prepared sheet, forming a rough rectangle.
03 - Place the chopped chocolate in a microwave-safe bowl and heat in 20-second intervals, stirring between each burst, until completely smooth and glossy.
04 - Pour the melted chocolate evenly over the arranged banana slices. Use a spatula to gently spread the chocolate, ensuring all banana pieces are fully covered.
05 - Drizzle peanut butter over the chocolate layer if using. Scatter chopped roasted nuts, mini chocolate chips or cacao nibs, and a pinch of flaky sea salt across the surface.
06 - Transfer the baking sheet to the freezer and chill for at least 45 to 60 minutes, or until the bark is completely firm and hardened throughout.
07 - Remove from the freezer and break or cut the bark into irregular pieces. Serve immediately while cold for the best crunchy texture.