Open the can of chickpeas and drain the chickpea water (aquafaba) through a strainer into a medium-size glass bowl (make sure the bowl is grease-free and dry). Whisk the aquafaba with a hand mixer on high speed until stiff peaks form. It should take about 5-10 minutes. If you tilt the bowl and the aquafaba slides down, keep whipping. Then slowly add the granulated sugar while the mixer is running and mix for about 3-5 minutes.
Place finely chopped dark chocolate bar in a glass bowl, and put it over a small pot with just-boiled water (don't let the bottom of the bowl touch hot water). Let the chocolate slowly heat up and melt. Mix it through a few times. Once the chocolate is melted, take the bowl off the heat, and allow the chocolate to cool down a little (it should not be warm to touch).
Gently and gradually fold the melted chocolate into the whipped aquafaba using a spatula (it will deflate a bit once you combine it). Make sure that no chocolate drop to the bottom of the bowl. Be careful not to overmix.
Divide the mixture into 4 smaller glasses. Put them into the fridge and let chill for at least 3 hours, ideally overnight, to set.
Coconut Whipped Cream: Add coconut cream and powdered sugar to a mixing bowl and whip it with a hand mixer until light and fluffy and small peaks form.
Serve chilled chocolate mousse with coconut whipped cream, chocolate shavings, or fresh berries.
Enjoy!