Begin by cutting the ripe avocados in half and removing the pits. Scoop the flesh into a blender or food processor.
Add the unsweetened cocoa powder, maple syrup, coconut milk, vanilla extract, and a pinch of salt to the blender with the avocado.
Blend the mixture on high speed until it becomes smooth and creamy. You may need to stop and scrape down the sides of the blender to ensure everything is well combined.
Taste the mousse and adjust sweetness if necessary. You can add more maple syrup if you prefer a sweeter mousse.
Once blended to a silky consistency, transfer the mousse into individual serving dishes or a large bowl.
Refrigerate for at least 30 minutes to allow the mousse to set and the flavors to meld.
Serve chilled, garnished with fresh berries, nuts, or a dollop of coconut whipped cream if desired.