Cut the avocados in half, remove the pits, and scoop the flesh into a food processor or high-speed blender.
Add cocoa powder, maple syrup, melted chocolate, vanilla extract, and salt to the avocado.
Blend until smooth and creamy, scraping down the sides as needed. If the mixture is too thick, add almond milk one tablespoon at a time until desired consistency is reached.
Taste and adjust sweetness if necessary.
Transfer the mousse to serving bowls or glasses.
Chill in the refrigerator for at least 2 hours to allow the flavors to meld and the mousse to set.
Before serving, garnish with fresh berries, a sprinkle of cocoa powder, or a dollop of coconut whipped cream.