With an electric mixer, combine all ingredients for the first layer.
Line a small pan with parchment paper. Transfer the mixture for the first layer into it. Refrigerate for 10 minutes while making the second layer.
To make the second layer, mix peanut butter, sugar-free maple syrup and dark chocolate in a bowl. Melt in the microwave if needed. Stir until well combined.
Let it cool for a while then pour over the first layer. Freeze for at least 40 minutes.
Once ready, cut into 18 squares. Serve them with melted chocolate if desired.