Steps
1. Melt the dark chocolate gently in a heatproof bowl over simmering water or in short bursts in the microwave, stirring until smooth.
2. Cut the avocado in half, remove the pit, and scoop the flesh into a blender or food processor.
3. Add the melted chocolate, maple syrup, vanilla extract, and a pinch of salt to the avocado.
4. Blend until smooth and creamy, scraping down the sides as needed.
5. Spoon the mousse into a serving dish or glass.
6. Chill in the refrigerator for at least 30 minutes to set.
7. Before serving, top with fresh mixed berries and garnish with mint leaves if desired.