Melt the butter in a small saucepan or microwave. Line a loaf pan with baking or parchment paper.

Mix peanut butter, stevia and HALF (50g / 1.7oz) THE MELTED BUTTER in a small bowl. Spoon the mixture into your prepared pan. Try and flatten evenly. Pop in the freezer to set.

Meanwhile, break chocolate into small chunks and add to the remaining butter. Stand for 5 minutes to melt the chocolate.

When the chocolate has melted, stir to combine with the butter. Smooth the chocolate mixture over the peanut butter layer.

Freeze until firm – about 20 minutes.